wined3d: Move shader generation into the shader backend.

Generating the shader ID and parts of the shader prolog and epilog was
done by the common vertexshader.c / pixelshader.c, which is ugly.

This patch doesn't get rid of all the uglyness, somewhen we'll still
have to sort out the relationship of [arb|glsl]_generate_shader and
[arb|glsl]_generate_declarations.
6 files changed