* Created GameSave class.

* Created GameSaveXMLWriter class.
* Created Rectangle class (for collision detection).
* Renamed CharacterBase class to Character class.
* Replaced HumanPlayer class with Character class.
* Deleted HumanPlayer class & unit test.
* Refactored Armor class & unit test.
* Refactored Weapon class & unit test.
* Refactored Character class & unit test.
* Refactored RPGgame class to test AI behavior; screen changes color according to direction traveled.