- removed obsolete colormap stuff from FHardwareTexture.
restructured shaders so that the light and texel parts are processed separately.

This required an alteration in the HardwareShader interface, meaning that old custom shaders which manipulate the light color won't work anymore.
use a special stripped down to the barest minimum shader for filling stencils.

Of all rendering operations these are the ones with the highest potential to stall the CPU and they do not need any special processing, plus they are a very easy candidate for replacement.
- cleaned up the shader function interface.
- fixed some oversimplification in the foglayer shader (this shader needs to go away!)
- since we are now doing the alpha test for unlit texels a lot of maintenance for the alpha function can be removed because for most things it can remain at its default setting now.
- we no longer need to maintain the view and projection matrix in the render state.
- some cleanup.
- read clip plane from frame state.
- stencil shaders were a bit oversimplified.