r_glsl_deluxemapping 2 support for vertexlit surfaces, deluxemap forced surfaces...

r_glsl_deluxemapping 2 support for vertexlit surfaces, deluxemap forced surfaces no longer use texture2d(deluxemap). Attempt to fix '2D pics GLSL gamma with sRGB', added v_glslgamma_2d (default 0). New "dprtlightambient" shader keyword which adds ambient rtlight to surface, useful on lowpoly harsh entities (like grass bushes) for smoother rtlightning. New trick: CSQC sound/pointsound plugins take "#sound_index" which can be returned by precache_sound.

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@11262 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=a14d8ac6ca1ca641b68a666983531298ee036576