Switch to glowutils::Camera

...to be able to take advantage of glow's CameraPath capabilities lateron. 
* The integration overwrites glowutils::Camera center and up with our quaternion-based orientation-approach.
* update the glow submodule, as it adds the projecitonOffset needed for the Oculus. 
* Fix crash on run with -stereo, as the HUD had an already deleted MonoView. No clean solution, but I told you this HUD-hold-the-view thing is no good idea.

I will talk to the glowsquad about the first 2 points.