Added support for 2D shadow casters.
*DANGER* Shaders in CanvasItem CHANGED, if you are using shader in a
CanvasItem and pull this, you will lose them. Shaders now work through a
2D material system similar to 3D. If you don't want to lose the 2D
shader code, save the shader as a .shd, then create a material in
CanvasItem and re-assign the shader.
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-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
-fix some menus
-fixed bug in out transition curves
-detect and remove file:/// in collada
-remove multiscript for now
-remove dependencies on mouse in OS, moved to Input
-avoid fscache from screwing up (fix might make it slower, but it works)
-funcref was missing, it's there now
In the `parse_tag` method of the `class ResourceInteractiveLoaderXML`,
the class responsible of loading the editor_settings.xml file, the
properties' values are loaded directly into an `String` object but the
file contents are always UTF-8, which leads to garbage in the XML file
when saved.
This patch reads the properties' values in a `CharString` and translate
them to UTF-8.
