[5/5] wined3d: Handle texture coordinates the same way we handle other vertex attributes

[Stefan Dösinger]

> Yeah, although I wouldn't be opposed to simply making ARB_multitexture
> a hard requirement either. I doubt there are any configurations left
> that don't support multitexture but that would otherwise be able to
> run Wine.
I guess(and we discussed that on IRC, just adding it for the sake of the archives) that we can happily emulate ARB_multitexture with a texture limit of 1 texture if it isn't supported if we really want compatibility for such old cards. That should free us from quite a a few ugly and needlessly expensive if checks