Sigh support sucky APPLE os, which only have a really old OpenGL

NOTE: Added possibility to display Normal/Bump maps with Hemilight and EnvMap
Shaders, if OpenGL version/drivers is good enough.
Merge remote-tracking branch 'origin/dgud/fix-shaders-apple-sucks' into dgud/normalmap-bug
Cleanup shader handling (fix normal shaders on GL-2.1)