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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-Fixed problem with scaling shapes (#827), related to not taking scale in consideration for calculating the moment of inertia
-Added support for multiline strings (or comments) using """
-Save subscene bug, properties not being saved in root node (#806)
-Fix Crash in CollisionPolygon2DEditor (#814)
-Restored Ability to compile without 3D (#795)
-Fix InterpolatedCamera (#803)
-Fix UV Import for OBJ Meshes (#771)
-Fixed issue with modifier gizmos (#794)
-Fixed CapsuleShape gizmo handle (#50)
-Fixed Import Button (not properly working in 3D) (#733)
-Many misc fixes (though no new features)