Fixes the following GCC 5 warnings:
```
core/io/zip_io.h:128:26: warning: 'zlib_filefunc_def zipio_create_io_from_file(FileAccess**)' defined but not used [-Wunused-function]
core/script_debugger_remote.cpp:110:17: warning: 'ObjectID safe_get_instance_id(const Variant&)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:103:12: warning: 'int _socket_create(IP::Type&, int, int)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:45:15: warning: 'size_t _set_sockaddr(sockaddr_storage*, const IP_Address&, int, IP::Type)' defined but not used [-Wunused-function]
drivers/unix/socket_helpers.h:76:15: warning: 'size_t _set_listen_sockaddr(sockaddr_storage*, int, IP::Type, IP_Address)' defined but not used [-Wunused-function]
editor/editor_fonts.cpp:40:24: warning: 'Ref<BitmapFont> make_font(int, int, int, int, const int*, const Ref<Texture>&)' defined but not used [-Wunused-function]
editor/editor_themes.cpp:85:26: warning: 'Ref<StyleBoxFlat> change_border_color(Ref<StyleBoxFlat>, Color)' defined but not used [-Wunused-function]
editor/import/editor_import_collada.cpp:493:13: warning: 'void _generate_normals(const PoolVector<int>&, const PoolVector<Vector3>&, PoolVector<Vector3>&)' defined but not used [-Wunused-function]
editor/import/editor_import_collada.cpp:524:13: warning: 'void _generate_tangents_and_binormals(const PoolVector<int>&, const PoolVector<Vector3>&, const PoolVector<Vector3>&, const PoolVector<Vector3>&, PoolVector<float>&)' defined but not used [-Wunused-function]
editor/pvrtc_compress.cpp:118:13: warning: 'void _compress_etc(Image*)' defined but not used [-Wunused-function]
modules/etc/image_etc.cpp:89:13: warning: 'void _decompress_etc1(Image*)' defined but not used [-Wunused-function]
modules/etc/image_etc.cpp:93:13: warning: 'void _decompress_etc2(Image*)' defined but not used [-Wunused-function]
modules/gdscript/editor/gdscript_highlighter.cpp:46:13: warning: 'bool _is_whitespace(CharType)' defined but not used [-Wunused-function]
scene/2d/cpu_particles_2d.cpp:510:14: warning: 'float rand_from_seed_m1_p1(uint32_t&)' defined but not used [-Wunused-function]
scene/3d/cpu_particles.cpp:474:14: warning: 'float rand_from_seed_m1_p1(uint32_t&)' defined but not used [-Wunused-function]
scene/resources/default_theme/default_theme.cpp:123:20: warning: 'Ref<Shader> make_shader(const char*, const char*, const char*)' defined but not used [-Wunused-function]
scene/resources/default_theme/default_theme.cpp:130:24: warning: 'Ref<BitmapFont> make_font(int, int, int, int, const int*, const Ref<Texture>&)' defined but not used [-Wunused-function]
```
Had to split `core/io/zip_io.h` into header and .cpp file without 'static' keyword.
Not fixed yet (static definition in header used in some files but not all):
```
modules/websocket/lws_helper.h:111:13: warning: 'void _lws_make_protocols(void*, int (*)(lws*, lws_callback_reasons, void*, void*, size_t), PoolVector<String>, _LWSRef**)' defined but not used [-Wunused-function]
```
Also fixed a couple other warnings missed in previous commits.
Fixes the following GCC 5 warnings:
```
core/object.h:193:11: warning: 'MethodInfo::flags' will be initialized after [-Wreorder]
core/object.h:192:15: warning: 'PropertyInfo MethodInfo::return_val' [-Wreorder]
core/object.cpp:278:1: warning: when initialized here [-Wreorder]
core/script_debugger_remote.h:97:6: warning: 'ScriptDebuggerRemote::max_cps' will be initialized after [-Wreorder]
core/script_debugger_remote.h:91:6: warning: 'int ScriptDebuggerRemote::max_messages_per_frame' [-Wreorder]
core/script_debugger_remote.cpp:1086:1: warning: when initialized here [-Wreorder]
core/script_debugger_remote.h:98:6: warning: 'ScriptDebuggerRemote::char_count' will be initialized after [-Wreorder]
core/script_debugger_remote.h:92:6: warning: 'int ScriptDebuggerRemote::n_messages_dropped' [-Wreorder]
core/script_debugger_remote.cpp:1086:1: warning: when initialized here [-Wreorder]
modules/bullet/area_bullet.h:102:7: warning: 'AreaBullet::isScratched' will be initialized after [-Wreorder]
modules/bullet/area_bullet.h:92:39: warning: 'PhysicsServer::AreaSpaceOverrideMode AreaBullet::spOv_mode' [-Wreorder]
modules/bullet/area_bullet.cpp:46:1: warning: when initialized here [-Wreorder]
modules/bullet/collision_object_bullet.h:127:15: warning: 'CollisionObjectBullet::space' will be initialized after [-Wreorder]
modules/bullet/collision_object_bullet.h:117:7: warning: 'CollisionObjectBullet::Type CollisionObjectBullet::type' [-Wreorder]
modules/bullet/collision_object_bullet.cpp:67:1: warning: when initialized here [-Wreorder]
modules/bullet/godot_ray_world_algorithm.h:48:7: warning: 'GodotRayWorldAlgorithm::m_ownManifol1d' will be initialized after [-Wreorder]
modules/bullet/godot_ray_world_algorithm.h:46:33: warning: 'const btDiscreteDynamicsWorld* GodotRayWorldAlgorithm::m_world' [-Wreorder]
modules/bullet/godot_ray_world_algorithm.cpp:50:1: warning: when initialized here [-Wreorder]
modules/bullet/godot_result_callbacks.h:91:18: warning: 'GodotAllConvexResultCallback::m_exclude' will be initialized after [-Wreorder]
modules/bullet/godot_result_callbacks.h:89:6: warning: 'int GodotAllConvexResultCallback::m_resultMax' [-Wreorder]
modules/bullet/godot_result_callbacks.h:93:2: warning: when initialized here [-Wreorder]
modules/bullet/godot_result_callbacks.h:142:18: warning: 'GodotAllContactResultCallback::m_exclude' will be initialized after [-Wreorder]
modules/bullet/godot_result_callbacks.h:140:6: warning: 'int GodotAllContactResultCallback::m_resultMax' [-Wreorder]
modules/bullet/godot_result_callbacks.h:147:2: warning: when initialized here [-Wreorder]
modules/bullet/godot_result_callbacks.h:168:18: warning: 'GodotContactPairContactResultCallback::m_exclude' will be initialized after [-Wreorder]
modules/bullet/godot_result_callbacks.h:166:6: warning: 'int GodotContactPairContactResultCallback::m_resultMax' [-Wreorder]
modules/bullet/godot_result_callbacks.h:173:2: warning: when initialized here [-Wreorder]
modules/bullet/godot_result_callbacks.h:195:18: warning: 'GodotRestInfoContactResultCallback::m_exclude' will be initialized after [-Wreorder]
modules/bullet/godot_result_callbacks.h:191:7: warning: 'bool GodotRestInfoContactResultCallback::m_collided' [-Wreorder]
modules/bullet/godot_result_callbacks.h:199:2: warning: when initialized here [-Wreorder]
modules/bullet/rigid_body_bullet.h:200:9: warning: 'RigidBodyBullet::gravity_scale' will be initialized after [-Wreorder]
modules/bullet/rigid_body_bullet.h:199:9: warning: 'real_t RigidBodyBullet::mass' [-Wreorder]
modules/bullet/rigid_body_bullet.cpp:258:1: warning: when initialized here [-Wreorder]
modules/bullet/rigid_body_bullet.h:222:28: warning: 'RigidBodyBullet::force_integration_callback' will be initialized after [-Wreorder]
modules/bullet/rigid_body_bullet.h:219:7: warning: 'bool RigidBodyBullet::isTransformChanged' [-Wreorder]
modules/bullet/rigid_body_bullet.cpp:258:1: warning: when initialized here [-Wreorder]
modules/bullet/rigid_body_bullet.h:220:7: warning: 'RigidBodyBullet::previousActiveState' will be initialized after [-Wreorder]
modules/bullet/rigid_body_bullet.h:208:6: warning: 'int RigidBodyBullet::maxCollisionsDetection' [-Wreorder]
modules/bullet/rigid_body_bullet.cpp:258:1: warning: when initialized here [-Wreorder]
modules/bullet/soft_body_bullet.h:69:9: warning: 'SoftBodyBullet::total_mass' will be initialized after [-Wreorder]
modules/bullet/soft_body_bullet.h:68:6: warning: 'int SoftBodyBullet::simulation_precision' [-Wreorder]
modules/bullet/soft_body_bullet.cpp:38:1: warning: when initialized here [-Wreorder]
modules/bullet/soft_body_bullet.h:76:9: warning: 'SoftBodyBullet::drag_coefficient' will be initialized after [-Wreorder]
modules/bullet/soft_body_bullet.h:61:14: warning: 'btSoftBody* SoftBodyBullet::bt_soft_body' [-Wreorder]
modules/bullet/soft_body_bullet.cpp:38:1: warning: when initialized here [-Wreorder]
modules/bullet/space_bullet.h:97:22: warning: 'SpaceBullet::solver' will be initialized after [-Wreorder]
modules/bullet/space_bullet.h:95:35: warning: 'btDefaultCollisionConfiguration* SpaceBullet::collisionConfiguration' [-Wreorder]
modules/bullet/space_bullet.cpp:333:1: warning: when initialized here [-Wreorder]
modules/bullet/space_bullet.h:101:23: warning: 'SpaceBullet::soft_body_world_info' will be initialized after [-Wreorder]
modules/bullet/space_bullet.h:99:23: warning: 'btGhostPairCallback* SpaceBullet::ghostPairCallback' [-Wreorder]
modules/bullet/space_bullet.cpp:333:1: warning: when initialized here [-Wreorder]
modules/gdnative/nativescript/nativescript.h:79:13: warning: 'NativeScriptDesc::base_native_type' will be initialized after [-Wreorder]
modules/gdnative/nativescript/nativescript.h:73:9: warning: 'String NativeScriptDesc::documentation' [-Wreorder]
modules/gdnative/nativescript/nativescript.h:88:9: warning: when initialized here [-Wreorder]
modules/gdscript/gdscript.h:296:6: warning: 'GDScriptWarning::line' will be initialized after [-Wreorder]
modules/gdscript/gdscript.h:294:4: warning: 'GDScriptWarning::Code GDScriptWarning::code' [-Wreorder]
modules/gdscript/gdscript.h:303:2: warning: when initialized here [-Wreorder]
scene/3d/physics_body.h:544:7: warning: 'PhysicalBone::simulate_physics' will be initialized after [-Wreorder]
scene/3d/physics_body.h:543:7: warning: 'bool PhysicalBone::_internal_static_body' [-Wreorder]
scene/3d/physics_body.cpp:2502:1: warning: when initialized here [-Wreorder]
scene/3d/physics_body.h:546:6: warning: 'PhysicalBone::bone_id' will be initialized after [-Wreorder]
scene/3d/physics_body.h:539:12: warning: 'Skeleton* PhysicalBone::parent_skeleton' [-Wreorder]
scene/3d/physics_body.cpp:2502:1: warning: when initialized here [-Wreorder]
scene/3d/spring_arm.h:44:11: warning: 'SpringArm::mask' will be initialized after [-Wreorder]
scene/3d/spring_arm.h:43:8: warning: 'float SpringArm::current_spring_length' [-Wreorder]
scene/3d/spring_arm.cpp:37:1: warning: when initialized here [-Wreorder]
scene/animation/skeleton_ik.h:159:11: warning: 'SkeletonIK::target_node_override' will be initialized after [-Wreorder]
scene/animation/skeleton_ik.h:152:7: warning: 'bool SkeletonIK::use_magnet' [-Wreorder]
scene/animation/skeleton_ik.cpp:418:1: warning: when initialized here [-Wreorder]
scene/resources/tile_set.h:84:9: warning: 'TileSet::AutotileData::size' will be initialized after [-Wreorder]
scene/resources/tile_set.h:83:7: warning: 'int TileSet::AutotileData::spacing' [-Wreorder]
scene/resources/tile_set.h:92:12: warning: when initialized here [-Wreorder]
scene/resources/tile_set.h:115:12: warning: 'TileSet::TileData::tile_mode' will be initialized after [-Wreorder]
scene/resources/tile_set.h:114:9: warning: 'Color TileSet::TileData::modulate' [-Wreorder]
scene/resources/tile_set.h:120:12: warning: when initialized here [-Wreorder]
servers/physics/body_sw.h:84:19: warning: 'BodySW::direct_state_query_list' will be initialized after [-Wreorder]
servers/physics/body_sw.h:57:11: warning: 'uint16_t BodySW::locked_axis' [-Wreorder]
servers/physics/body_sw.cpp:756:1: warning: when initialized here [-Wreorder]
```
Nothing really relevant for us, but it's not a bad consistency
improvement anyway so worth taking.
It was Godot-ified and integrated into Tween originally (#628)
without mention that it was thirdparty code, but it's actually
derived from https://github.com/jesusgollonet/ofpennereasing.
It's also very bad quality code and should be replaced by a better,
properly-maintained library of easing equations.
Fixes GCC 5 warnings of the form:
core/io/http_client.cpp:288:9: warning: enumeration value 'STATUS_SSL_HANDSHAKE_ERROR' not handled in switch [-Wswitch]
core/io/marshalls.cpp:806:9: warning: enumeration value 'AABB' not handled in switch [-Wswitch]
Those can be trivial cases where adding a default fallback is the solution,
or more complex issues/hidden bugs where missed values are actually meant
to be handled.
Fixes the following GCC 5 warnings:
```
core/os/file_access.cpp:49:19: warning: the address of 'FileAccess::create_func' will always evaluate as 'true' [-Waddress]
servers/audio_server.cpp:192:70: warning: comparison with string literal results in unspecified behaviour [-Waddress]
drivers/gles2/rasterizer_storage_gles2.cpp:4095:90: warning: NULL used in arithmetic [-Wpointer-arith]
modules/gdnative/register_types.cpp:237:3: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
platform/android/export/export.cpp:207:1: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
modules/gdscript/gdscript.h:150:67: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:119:56: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:123:56: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:127:50: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:131:52: warning: returning reference to temporary [-Wreturn-local-addr]
editor/plugins/skeleton_editor_plugin.cpp:34:36: warning: extra tokens at end of #include directive
modules/bullet/bullet_types_converter.cpp:31:9: warning: #pragma once in main file
editor/import/editor_scene_importer_gltf.cpp:1996:51: warning: name lookup of 'i' changed
modules/visual_script/visual_script_property_selector.cpp:402:45: warning: name lookup of 'E' changed
scene/gui/tree.cpp:1268:25: warning: name lookup of 'i' changed
scene/resources/visual_shader.cpp:808:32: warning: name lookup of 'i' changed
```
Fixes the following GCC 5 warnings:
```
drivers/gles2/rasterizer_canvas_gles2.cpp:814:8: warning: variable 'rt_size' set but not used [-Wunused-but-set-variable]
drivers/gles2/rasterizer_scene_gles2.cpp:2270:11: warning: variable 'vp_height' set but not used [-Wunused-but-set-variable]
drivers/gles2/rasterizer_scene_gles2.cpp:2673:22: warning: variable 'e' set but not used [-Wunused-but-set-variable]
drivers/gles2/rasterizer_scene_gles2.cpp:715:7: warning: variable 'no_cull' set but not used [-Wunused-but-set-variable]
drivers/gles2/shader_gles2.cpp:693:14: warning: variable 'cc' set but not used [-Wunused-but-set-variable]
drivers/gles3/rasterizer_canvas_gles3.cpp:1226:8: warning: variable 'rt_size' set but not used [-Wunused-but-set-variable]
drivers/gles3/rasterizer_scene_gles3.cpp:3039:10: warning: variable 'contrib' set but not used [-Wunused-but-set-variable]
drivers/gles3/rasterizer_scene_gles3.cpp:4504:32: warning: variable 'vp_height' set but not used [-Wunused-but-set-variable]
editor/editor_inspector.cpp:272:9: warning: variable 'guide_color' set but not used [-Wunused-but-set-variable]
editor/editor_themes.cpp:1067:14: warning: variable 'alpha3' set but not used [-Wunused-but-set-variable]
editor/editor_themes.cpp:263:8: warning: variable 'script_bg_color' set but not used [-Wunused-but-set-variable]
editor/plugins/collision_shape_2d_editor_plugin.cpp:326:11: warning: variable 'cpoint' set but not used [-Wunused-but-set-variable]
editor/plugins/mesh_editor_plugin.cpp:72:9: warning: variable 'size' set but not used [-Wunused-but-set-variable]
editor/plugins/shader_editor_plugin.cpp:471:12: warning: variable 'mpos' set but not used [-Wunused-but-set-variable]
editor/plugins/shader_editor_plugin.cpp:89:8: warning: variable 'basetype_color' set but not used [-Wunused-but-set-variable]
editor/plugins/shader_editor_plugin.cpp:90:8: warning: variable 'type_color' set but not used [-Wunused-but-set-variable]
editor/plugins/shader_editor_plugin.cpp:92:8: warning: variable 'string_color' set but not used [-Wunused-but-set-variable]
modules/visual_script/visual_script_editor.cpp:2521:7: warning: variable 'seq_connect' set but not used [-Wunused-but-set-variable]
platform/android/export/export.cpp:580:12: warning: variable 'styles_count' set but not used [-Wunused-but-set-variable]
platform/android/export/export.cpp:584:12: warning: variable 'styles_offset' set but not used [-Wunused-but-set-variable]
platform/osx/export/export.cpp:464:9: warning: variable 'zerr' set but not used [-Wunused-but-set-variable]
scene/2d/tile_map.cpp:260:10: warning: variable 'tcenter' set but not used [-Wunused-but-set-variable]
scene/3d/light.cpp:166:7: warning: variable 'editor_ok' set but not used [-Wunused-but-set-variable]
scene/3d/navigation.cpp:566:11: warning: variable 'closest_navmesh' set but not used [-Wunused-but-set-variable]
scene/gui/rich_text_label.cpp:869:8: warning: variable 'size' set but not used [-Wunused-but-set-variable]
scene/main/viewport.cpp:705:14: warning: variable 'xform' set but not used [-Wunused-but-set-variable]
scene/main/viewport.cpp:706:8: warning: variable 'ss' set but not used [-Wunused-but-set-variable]
scene/main/viewport.cpp:726:14: warning: variable 'xform' set but not used [-Wunused-but-set-variable]
scene/main/viewport.cpp:727:8: warning: variable 'ss' set but not used [-Wunused-but-set-variable]
scene/resources/material.cpp:430:7: warning: variable 'using_world' set but not used [-Wunused-but-set-variable]
servers/visual/shader_language.cpp:2026:7: warning: variable 'all_const' set but not used [-Wunused-but-set-variable]
servers/visual/visual_server_scene.cpp:1383:28: warning: variable 'z_max_cam' set but not used [-Wunused-but-set-variable]
```
Also fixes two [-Wunused-value] warnings:
```
scene/gui/text_edit.cpp:4405:20: warning: statement has no effect [-Wunused-value]
servers/visual/visual_server_scene.cpp:905:48: warning: value computed is not used [-Wunused-value]
```
Some of those are bugs and need further work, they are identified with
`// FIXME` comments.
Also turn off -Wsign-compare warnings in the future, we do not consider them important.
Fixes the following GCC 5 warnings:
```
core/node_path.cpp:279:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
core/oa_hash_map.h:169:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
core/oa_hash_map.h:314:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
drivers/gles2/shader_gles2.cpp:985:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
drivers/gles3/rasterizer_storage_gles3.cpp:1075:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
drivers/pulseaudio/audio_driver_pulseaudio.cpp:343:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
editor/editor_plugin.cpp:525:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
editor/editor_properties_array_dict.cpp:747:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
editor/plugins/spatial_editor_plugin.cpp:2078:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
editor/plugins/spatial_editor_plugin.cpp:4096:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
editor/plugins/sprite_editor_plugin.cpp💯20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/cvtt/image_compress_cvtt.cpp:122:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/cvtt/image_compress_cvtt.cpp:134:77: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/cvtt/image_compress_cvtt.cpp:339:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/etc/image_etc.cpp:222:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/gdnative/register_types.cpp:242:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/gdnative/register_types.cpp:258:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/opensimplex/simplex_noise.cpp:200:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/opensimplex/simplex_noise.cpp:222:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
modules/opensimplex/simplex_noise.cpp:246:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/android/export/export.cpp:1085:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/android/export/export.cpp:1489:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/android/export/export.cpp:1623:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/iphone/export/export.cpp:206:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/iphone/export/export.cpp:356:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/iphone/export/export.cpp:406:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
platform/iphone/export/export.cpp:493:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/3d/audio_stream_player_3d.cpp:420:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/resources/audio_stream_sample.cpp:565:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/resources/audio_stream_sample.cpp:571:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio/audio_rb_resampler.cpp:156:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
```
The following warnings were not fixed, as they implied casting for no gain:
```
core/io/packet_peer.cpp:228:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
core/io/resource_format_binary.cpp:109:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
drivers/gles2/rasterizer_scene_gles2.cpp:144:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
drivers/unix/file_access_unix.cpp:249:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/3d/voxel_light_baker.cpp:889:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/3d/voxel_light_baker.cpp:1020:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/3d/voxel_light_baker.cpp:1154:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/3d/voxel_light_baker.cpp:2255:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
scene/resources/bit_mask.cpp:336:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio/audio_stream.cpp:141:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio/audio_stream.cpp:150:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio/audio_stream.cpp:154:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio_server.cpp:86:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
servers/audio_server.cpp:89:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
```
Fixes the following GCC 5 warnings:
```
core/io/resource_format_binary.cpp:1721:29: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
core/typedefs.h:108:24: warning: suggest parentheses around comparison in operand of '!=' [-Wparentheses]
editor/plugins/spatial_editor_plugin.cpp:2202:58: warning: suggest parentheses around comparison in operand of '!=' [-Wparentheses]
editor/plugins/spatial_editor_plugin.cpp:5002:12: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
main/input_default.cpp:346:59: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
main/input_default.cpp:348:60: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
main/input_default.cpp:579:57: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
modules/gridmap/grid_map_editor_plugin.cpp:613:14: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
modules/theora/video_stream_theora.cpp:335:34: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
modules/theora/video_stream_theora.cpp:336:35: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
modules/visual_script/visual_script_property_selector.cpp:215:38: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
scene/gui/rich_text_label.cpp:424:84: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
scene/gui/rich_text_label.cpp:512:80: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
scene/gui/scroll_container.cpp:173:36: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
scene/gui/scroll_container.cpp:173:86: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
scene/gui/tree.cpp:1419:98: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
```
Better heuristic for the shortest path algorithm for navigation2D and navigation.
It now will use the shortest distance to the polygon as cost instead of the distance to the center.
