[WINED3D] Improve/implement D3DSIO_TEX (ps 1.0-3.0)

[Ivan Gyurdiev]

- unify per-version cases into a single sequence
- make use of get_register_name() for the destination register
- ignore destination write mask - it's only allowed on 2.0+ shaders, and 
only the default mask is allowed there (xyzw)
- enable swizzle on texld 1.4 (it works together with dw/dz modifiers)
- implement for shaders 2.0-3.0

Note:
The 2.0/3.0 implementation may be incomplete. It reads textures from a 
sampler, which has a declaration as a 2d/cube/volume type. We probably 
need to take that into account when sampling - currently only 2D is 
supported. However, I still think the patch should be applied, since it 
gets the 2D case working, and allows certain demos to proceed further - 
for example the MandelbrotSet demo: 
http://www.humus.ca/index.php?page=3D&&start=32