Patch 1 [see Notes]

Fixed Bugs:
  Health kits, etc disappearing on new level.
  Mysterious repeated 7th round replaced with a bonus level.  (Don't edit code on no sleep!)
  Going to round 14 now no longer crashes
  Fix physics bodies deleting twice (rare crash, sometimes exposed by going through all waves)

Fixed Issues:
  Reduced background tile contrast
  Added yellow circles around pickups to make them obvious
  Arrow Keys can now be used as alternative to WASD keys
  Updating the instructions and notes