redesigned how the renderer handles much of it's state (R_Mesh_State turned into...

batching is gone
VAR support is gone (but may make a return someday)
dynamic shadow volumes are now more optimized (removal of unused verts)
added a glossary of terminology to the start of r_shadow.c
added gl_mesh_testarrayelement and gl_mesh_testmanualfeeding cvars for testing/debugging purposes in the backend (incase vertex array state is a mess)
added gl_paranoid cvar (enables CHECKGLERROR and verifies geometry before rendering it)
added gl_printcheckerror cvar (prints location of every CHECKGLERROR statement as it executes, for tracking code flow)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@3119 d7cf8633-e32d-0410-b094-e92efae38249