merged static and dynamic rtlight handling almost entirely (even uses DrawShadowVolum...

merged static and dynamic rtlight handling almost entirely (even uses DrawShadowVolume and DrawLight to generate cached meshes - however this currently lost the r_shadow_portallight optimizations)
added a surfacelist to model_t containing surface indices for each submodel
merged R_Shadow_DiffuseLighting and R_Shadow_SpecularLighting into R_Shadow_RenderLighting (which takes a lighting parameter containing LIGHTING_DIFFUSE and LIGHTING_SPECULAR flags)
commented out cullradius/cullradius2 in rtlight structs because they weren't used

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@4015 d7cf8633-e32d-0410-b094-e92efae38249