Post-Mortem Changes

- Changed implementation of text from GUIText to Quad + TextMesh. This
solves the double vision problem.
- Changed the gameover behaviour so that it always appears in the middle
of the screen and is always on top, when using the oculus
- Created separated placements and scales of score text and game over
texture depending on wheter you have the oculus rift or not.

Problems left:
- non-oculus version: distorted projection, mouse only moves on x-axis
- sometimes the gameover screen doesn't appear
- sometimes when I press space from the main menu, it redirects me back
to the main menu again
- the main menu shows after each collission death(no game over screen
for looking away from paper)