Removed AttackButtonStore.
Added Flash White CALayer with options in Animator.
Increased default Attack Button lifetime from 5 to 9 seconds. Removed damage. Damage is now based on the button's time remaining when it is tapped.
Added a Button Spawn Controller that spawns a button when the appropriate notice is posted. If the button is an Attack Button, it sets some of its data. The Button Spawn Controller will only create a new button if its button is gone.
    The ButtonSpawnDelegate allows buttons to communicate with their Spawn Controller so that the controller will know that the button is about to destroy itself.
Changed Shield icon to something more "evil looking".
Changed button spawning in battle from random to specific - only Button Spawn Controllers will spawn them now.
Changed the effect of difficulty: The harder the difficulty, the more health enemies have, and the higher the chance that "evil" Shields appear.
    Higher difficulties reward extra experience: x2 Average, x3 Hard
Added an Image Store to cache images and improve performance.
Implemented a "cheat": tapping the Player icon at the top of the screen (in the Home Header View) removes all active evil Shields from the game.
Updated enemy JSON data to match changes - enemies have had their health increased and their time limits reduced slightly.