- Fake projective textures on a single texture unit. A fallback is only

- Fake projective textures on a single texture unit. A fallback is only
  needed if a second texture unit is enabled.
- Also worked around an application bug in Chromium B.S.U.: it sends 3D
  texture coordinates while only a 2D texture is enabled. This used to
  trigger a PTEX fallback. Now the 3rd coordinate is just ignored.
- Fixed the _savage_texnorm_stage to never normalize homogenous texture
  coordinates.