Misc Fixes

==========

-NOTIFICATION_WM_QUIT fixed on android (seems tha way this is reported changed in newer sdk)
-WIP implementation of APK Expansion APIs for publishing games larger than 50mb in Play Store
-Feaures in the new tutorials are all present in the sourcecode
-This (hopefully) should get rid of the animation list order getting corrupted
-Improved 3D Scene Importer (Skeletons, Animations and other stuff were not being merged). Anything missing?
-In code editor, the automatic syntax checker will only use file_exists() to check preload() else it might freeze the editor too much while typing if the preload is a big resource
-Fixed bugs in PolygonPathFinder, stil pending to do a node and a demo

tools/editor/plugins/shader_editor_plugin.h

@@ -99,6 +99,7 @@ class ShaderEditor : public Control {
 
 	ShaderTextEditor *vertex_editor;
 	ShaderTextEditor *fragment_editor;
+	ShaderTextEditor *light_editor;
 
 	void _tab_changed(int p_which);
 	void _menu_option(int p_optin);