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.
-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
