OpenCS settings

The Subview section is not yet implemented, but I would like people to try it out and provide feedback comments please.  There are some debug statements still in there, please ignore them ;-)

EDIT: now integrated with existing settings code
Regarding the settings "shadows" "shadows_pssm" and "render_refraction", you can not use them just yet. Enabling them will produce shaders that include these features, but on its own that is useless. We also need a way to render shadow maps, and render refraction/reflection maps (the relevant code from OpenMW would have to be ported). Since that's not implemented yet, the settings are useless atm.