Attacking

Added targeting and attacking for towers.  Basic game over state
added(game will exit)
Starting Camera System

Started camera system.  Need to create an interface for all game
objects.  Will create new branch and leave this one as a clean working
copy of the game
wrote MainMenuState

wrote MainMenuState, basically a game state that just contains the title
of the game and our names as creators, but also has a button that starts
the game.