Fixes the following GCC 7 warnings:
```
core/cowdata.h:269:47: warning: 'alloc_size' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/error_macros.h:163:26: warning: 'nearest_point' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/image.cpp:1579:5: warning: 'colormap_size' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/image.cpp:1582:12: warning: 'size_height' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/image.cpp:1590:23: warning: 'size_width' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/image.cpp:1599:29: warning: 'pixel_size' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/math/face3.cpp:207:15: warning: 'tri_max' may be used uninitialized in this function [-Wmaybe-uninitialized]
core/math/face3.cpp:209:15: warning: 'tri_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/rasterizer_scene_gles3.cpp:665:22: warning: 'best_used_frame' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/rasterizer_storage_gles3.cpp:865:27: warning: 'blit_target' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/rasterizer_storage_gles3.cpp:980:29: warning: 'blit_target' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/shader_gles3.h:122:9: warning: '<anonymous>.ShaderGLES3::Version::frag_id' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/shader_gles3.h:122:9: warning: '<anonymous>.ShaderGLES3::Version::id' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/gles3/shader_gles3.h:122:9: warning: '<anonymous>.ShaderGLES3::Version::vert_id' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/plugins/script_editor_plugin.cpp:1980:31: warning: 'se' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/scene_tree_dock.cpp:840:30: warning: 'new_node' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4259:9: warning: 'a1' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4259:9: warning: 'lll' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4259:9: warning: 'lul' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4260:9: warning: 'a2' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4261:9: warning: 'a3' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4265:3: warning: 'enable_lin' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4294:3: warning: 'enable_ang' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4311:34: warning: 'll' may be used uninitialized in this function [-Wmaybe-uninitialized]
editor/spatial_editor_gizmos.cpp:4311:34: warning: 'ul' may be used uninitialized in this function [-Wmaybe-uninitialized]
scene/3d/voxel_light_baker.cpp:1655:47: warning: 'cone_dirs' may be used uninitialized in this function [-Wmaybe-uninitialized]
scene/3d/voxel_light_baker.cpp:1656:73: warning: 'cone_weights' may be used uninitialized in this function [-Wmaybe-uninitialized]
scene/gui/texture_progress.cpp:181:6: warning: 'cp' may be used uninitialized in this function [-Wmaybe-uninitialized]
scene/gui/texture_progress.cpp:181:6: warning: 'cq' may be used uninitialized in this function [-Wmaybe-uninitialized]
servers/physics/shape_sw.cpp:1056:19: warning: 'support_max' may be used uninitialized in this function [-Wmaybe-uninitialized]
```
This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.
This commit makes operator[] on Vector const and adds a write proxy to it. From
now on writes to Vectors need to happen through the .write proxy. So for
instance:
Vector<int> vec;
vec.push_back(10);
std::cout << vec[0] << std::endl;
vec.write[0] = 20;
Failing to use the .write proxy will cause a compilation error.
In addition COWable datatypes can now embed a CowData pointer to their data.
This means that String, CharString, and VMap no longer use or derive from
Vector.
_ALWAYS_INLINE_ and _FORCE_INLINE_ are now equivalent for debug and non-debug
builds. This is a lot faster for Vector in the editor and while running tests.
The reason why this difference used to exist is because force-inlined methods
used to give a bad debugging experience. After extensive testing with modern
compilers this is no longer the case.
Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.