- Implement D3DSIO_DP2ADD, D3DSIO_TEXKILL, D3DSIO_TEXM3X3PAD
- Partially implement D3DSIO_TEXBEM, D3DSIO_TEXM3X3VSPEC (as much as
  they are implemented in ARB_fragment_program at least).
- Stop copying the SHADER_PARSE_STATE struct in each ARB shader
  routine - use a pointer instead.