Major Update #3 (0.1.3) (See desc. for details)

- Lowest program 'module' changed from Module to IndependentUnit (Module
now exists as its own IndependentUnit, or effectively a Game object with
no UI)
- Refactored Module's initialize() to initializeModule()
- Refactored variables to match change from Module to IndependentUnit
- UI listeners added
- Added adapter classes for existing listeners
- Keyboard class mostly finished, several functions missing
- Overlays now implemented, mostly functional
- Plugin API started, mostly functional but very limited
- Refactoring of certain packages and movement of classes (i.e.
GameObject to the 'ui' package instead of the 'game' package)