Hi readers, for SRB2 vanilla shaders, reference
https://git.do.srb2.org/STJr/SRB2/blob/prerelease/src/hardware/r_opengl/r_opengl.c#L630

For accepted shader config names, reference
https://git.do.srb2.org/STJr/SRB2/blob/prerelease/src/hardware/hw_main.c#L6669

For available uniforms, reference
https://git.do.srb2.org/STJr/SRB2/blob/prerelease/src/hardware/r_opengl/r_opengl.c#L2129
https://git.do.srb2.org/STJr/SRB2/blob/prerelease/src/hardware/r_opengl/r_opengl.c#L583
Note: the sampler2D uniform can be any name

sh_DefaultFS.glsl is unused.

This was updated from 2.2.5-ish to 2.2.9 pre-release, 
these aren't likely to change on final release, or for a while after.

Changes from initial version: 
	Addition of model lighting vertex and fragment shader.
	Updated sky fragment shader.
	Changed some header comments.
	
Note: The ambient lighting option in opengl settings is ignored.