Holey Title, Batman

I have been busily rewriting the entire shader definition system to be more flexible and converting all the existing shaders over to the new system. The end result of all this is... nothing changes.

That's not exactly true. Some new features come out of this, just because a new framework makes them easier to implement. For example, masks selected by a layer selection texture can now cast shadows. There are also a lot less classes and clutter around shadow shaders in general, but that's more difficult to illustrate with an image.