Where possible, symbols have been made static, prefixed with glsl_/GLSL_ or
moved into the code shared by all renderers. This will make doing plugins
easier but done now for link testing. The moving was done via the gl
commit.
Add GLSL directory to QF and use it for all gsls based code (instead of
GL). defines.h, types.h and funcs.h are derived from gl2.h from khronos.
Text drawing now uses triangles instead of quads.
