When picking a color halfway between 100% white (0xffffffff) and fully
transparent (0x00000000), the result was 50% opaque 50% grey
(0x80808080) when it should really be 50% opaque white (0x80ffffff).
This had a tendency to create grey fringes on things. The fix is to
weight the non-alpha components based on how much they contribute to
the final alpha value.

The cache_entries' storages are just references to the same object anyway.

Mapping colorop to pixelshader is necessary because misc_state_template
defines a pixel shader handler. We have to use the same representative
in all pipeline parts.

Wined3d_cs_exec_set_texture dirtifies the pixel shader state when the
fixup of a texture changes. Atifs no longer needs a pixel shader handler
on its own since vertex shader updates aren't delayed any more when the
pixel shader state is dirty.

The abilities of this hardware is too limited to support generic sign /
swizzle fixups. A generic handler would consume 4 of the 8 available
color instruction slots and 2 alpha instruction slots.

The bump mapping handler code has its own way of handling the color
fixups. It merges the fixup into the perturbation calculation without
requiring extra shader instructions. In theory this is possible for the
majority of d3d texture ops as well, but I don't think this is worth the
effort. I expect that this code will only be used for the ddraw signed
format test in practice.