Doomsday Engine

Continued work on revising the interface to RL_AddPoly. Everything is once again working other than the case of surfaces drawn with a modulation texture (first light on surface). For now, disable multi-textured lights "rend-light-multitex 0" until the problem is resolved.

• Revised world texture coordinate generation. Now uses the OpenGL texture matrix for the translation and scaling of all texture units on world surface polyons. This means that potentially, we can get rid of the global texcoord buffer (and let OpenGL calculate them for us).
• Fixed problems introduced in the last batch of changes with fakeradio shadow segs and shiny surfaces.