[WIP] New example : core/vr_simulator

[Hultan]

[WIP] - Do not merge yet

I am starting to believe that the new VR functions (#429) are not correctly implemented. I cannot get the sample core/vr_simulator to work, and I have looked over the code again and again and cannot find any differences.

Since the VR functions were added earlier today, I figured that they have never been tested. Can someone try this example out on their computer and see if it works there?

All I get is a blank screen (with a FPS counter).