Added a GameState system. This allows easy switching between different "states" of the game, such as the title screen, main game, inventory screen, etc.
Added an abstract GameState adapter so we don't have to implement every single one of those listener methods.
This class is meant to handle all the JFrame, JPanel, and listener stuff for us.
Split up the com.amf.game package into com.amf.game.mike and com.amf.game.nelson. Implemented my game using the new GameState system with an example title screen state.
Merge pull request #5 from mfrancis95/mike

GameState System
Removed the old MikeGame and NelsonGame.
Merge origin/master into ross
Added Barricade and Zambie to extend Entity. Also added Direction enum and properties to entities