OpenGL: more work on fixed function lighting implementation as GLSL.

* Rename functions and move to own header.
* Add wrapper functions for glLight.
* Auto detect if we can use faster code for solid lighting.
* Various fixes for textured draw mode.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55166 954f8c5b-7b00-dc11-b283-0030488c597c