Update to ScreenManager, changes the system to a more MVVM structure by giving created objects reference to their containing GameScreens. Additionally, changes the Map loading scheme/XMLDeserialization to follow the MSDN standard of 1. creation, 2. deserialization. This means that classes that implement IXmlSerializable MUST supply a default constructor. This is so we can add GameScreen references to objects that require them without having to know things at compile time