Initial implementation of Power Up system.

Signed-off-by: Matt Cleveland <mgcleveland@gmail.com>
PowerIcon and Power class, along with first Power, PowerFireMissile,
implemented and working.

Signed-off-by: Matt Cleveland <mgcleveland@gmail.com>
Merged circle system along with power up system.

Merge remote-tracking branch 'Floor27mgc/power_system'

Conflicts:
	RecordRunnerARC.xcodeproj/project.pbxproj
	sources/GameLayer.m
	sources/GameObjectBase.h
	sources/Queue.h
	sources/Queue.m
	sources/common.h

Signed-off-by: Matt Cleveland <mgcleveland@gmail.com>