-Fixed crash with splash screen on windows

-properly show editor without having to resize window on windows

drivers/gles3/rasterizer_storage_gles3.cpp

@@ -6500,6 +6500,7 @@ void RasterizerStorageGLES3::initialize() {
 	frame.count = 0;
 	frame.prev_tick = 0;
 	frame.delta = 0;
+	frame.current_rt=NULL;
 	config.keep_original_textures = false;
 }
 

scene/main/scene_main_loop.cpp

@@ -2317,7 +2317,7 @@ SceneTree::SceneTree() {
 	stretch_aspect = STRETCH_ASPECT_IGNORE;
 
 	last_screen_size = Size2(OS::get_singleton()->get_video_mode().width, OS::get_singleton()->get_video_mode().height);
-	root->set_size(last_screen_size);
+	_update_root_rect();
 
 	if (ScriptDebugger::get_singleton()) {
 		ScriptDebugger::get_singleton()->set_request_scene_tree_message_func(_debugger_request_tree, this);

servers/visual/visual_server_raster.cpp

@@ -123,6 +123,7 @@ int VisualServerRaster::get_render_info(RenderInfo p_info) {
 
 void VisualServerRaster::set_boot_image(const Image &p_image, const Color &p_color, bool p_scale) {
 
+	redraw_request();
 	VSG::rasterizer->set_boot_image(p_image, p_color, p_scale);
 }
 void VisualServerRaster::set_default_clear_color(const Color &p_color) {