* Created Controller class for user input.

* Created EnemyAI class for enemy behavior.
* Created unit test for HumanPlayer class.
* Accessors modified in HumanPlayer class.
* Accessors modified in Inventory class.
* Accessors modified in Party class.
* Accessors modified in HumanPlayer class.
* Altered RPGGame class to interact with input by adding a Controller instance: inputs make the screen color change.