We assume it has the same capabilities as VOLUMETEXTURE. MSDN is very
vague on this topic. Intel/Nvidia/ATI drivers seem to offer nearly the
same caps on both, so do that too.

wined3d: When volume textures aren't around (GL_EXT_texture3D not supported) return WINED3DERR_NOTAVAILABLE.

wined3d: We don't offer index/vertex buffer caps. Neither do Windows drivers (at least Nvidia, Ati and Intel).

Also replace numeric ids by appropriate constants.

Structures containing enum fields without the v1_enum attribute must be
treated as complex because of the range check and memory/wire size
differences.  This includes a test which didn't pass before and now
passes on Wine and Windows.