Anaglyph stereo support

[MirceaKitsune]

This is probably a more uncommon feature for a RTS game, as visuals tend to matter less from a distant top view. But could support for anaglyph stereo be added to the engine? I have red & cyan glasses, and use them for many games that have stereo support. I think it would look nice for Glest too to see the environments and units in realistic depth