Clean up of current code

Cleaned up code
* Biggest change was architectural fix
* Added helper functions
* Lasers had edge cases that weren’t accounted for
* also added the 3 new level files
Added missing level files

Need to fix test class. Don’t have enough time for beta
Merge branch 'PowerUp_architecturalChanges' into PowerUPBeta

Conflicts:
	GameModel.h
	GameModel.m
	GameViewController.m
	Grid.h
	Grid.m
	PowerUP.xcodeproj/project.pbxproj
	PowerUP/level6
	PowerUP/level7
	PowerUP/level8