fixed realtime lighting bugs with gl_mesh_batching 1 (... by not using batching while...

fixed realtime lighting bugs with gl_mesh_batching 1 (... by not using batching while rendering realtime lighting - I was unable to figure out what was causing the problem)
some cleanups to realtime lighting code (mostly fixing some bugs with incorrect counting of meshes/triangles (for r_speeds reports), and optimized out unnecessary vertex copying in the final lighting application pass)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@3044 d7cf8633-e32d-0410-b094-e92efae38249