Since all material layers except the brightmaps are relatively rare encounters these were taken out of the main texture object and offloaded to a substructure that is only allocated on demand.
The main bulk of this is the new start screen code. To make this work in Raze some more work on the startup procedure is needed.
What this does provide is support for the DOS end-of-game text screens in Duke and SW on non-Windows systems.
Also added support for creating indexed textures directly into CreateTexBuffer, where this functionality can be shared.
As an added plus, brightmaps are working again, this time with less hackery.
