4D renderer with support for oculus rift. Not very interesting yet. Come back later.

* Setup 3d eye to 4d subspace conversion
* Fix 4d perspective projection
* Refactor collision to be 4d
* Setup eye 4d subspace mode toggling
* Re-add color based rendering, blending between normal lit and distance in 4d (red/blue?)
* Re-add backface and depth testing for 4d modes