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.

ddraw: Don't clear the return value anymore, we fill the fields anyway, also a test for the behaviour.

Adds rudimentary test for 8 bit mode ddraw (palettized primary surface). Tests 
things like GetDC and its palette handling and SetPalette affected by patches 
that follow.