- replaced alpha test and clip planes - both features which are deprecated in the core profile - with shader checks.
- code cleanup: removed some non-shader-only stuff from dynamic light and texture creation code.
- change handling of glowing walls: instead of passing the distance to the glowing flats for each single vertex, better pass the plane equations up front and do the distance calculations in the shader.
- take warp timer handling out of the shader class and move it to the render state class to have better control over the calls to glUniform for it.
- set colormaprange info at the start of each frame. This info is static per frame and setting it up fronts saves us from maintaining its state.
- fixed: the colormap shader did not compile because it was missing the pixelpos variable.
- removed the obsolete gl_SetupLight function.