BoUT2: Add shadow vertex shaders

More broken shadows a bit further on in Wilbur's room. The pixel shader I
alredy disabled doesn't seem to affect these and I couldn't seem to affect
them by changing the ones that did (not sure why - I probably just messed
something up).

I think at least one of these shaders was also used for shadows elsewhere.
BoUT2: ShaderConverter
BoUT2: Correct output of ShaderConverter

I keep hitting these (and the sincos one from yesterday) - I might want to
check if ShaderConverter is open source, and if not start re-implementing it.
BoUT2: Disable dynamic shadows in Wilbur's room

As before these can be toggled on and off with 7