worked around an ATI driver bug with glColor during GL_EXT_compiled_vertex_array...

worked around an ATI driver bug with glColor during GL_EXT_compiled_vertex_array locks being ignored - R_Shadow_RenderLighting dot3 paths now lock around each pass instead of the whole set of final passes - ATI PLEASE FIX THIS, the GL_EXT_compiled_vertex_array spec says all settings can be changed during a lock!
reorganized R_Shadow_RenderLighting to reduce code duplication a bit
enabled scissor without stencil support (the bug was in the lack of a valid projectmatrix)
added 3 tmu vertex lighting path (uses XYZ attenuation via textures, and vertex shading) which is mainly for use on 3+ tmu cards in 16bit color mode
renamed R_Shadow_VertexLighting functions to R_Shadow_VertexShading and made their names more clear
fixed a bug in the R_Shadow_VertexShading math (now normalizes the vertex->light vector as well as normal vector)
made some functions static
added an #ifndef USETEXMATRIX around the cpu matrix transform functions as they're not used anymore due to USETEXMATRIX code

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@4046 d7cf8633-e32d-0410-b094-e92efae38249