Updated Java2D and interfaces for displays.

Java2D will no longer contain its own list of Paintables. This should be handled
by the view instead. The list of Paintables sent to the display's update() will
be painted in the order of iteration (ex. LinkedList or ArrayList will be
painted first to last). We might want to change it to have different Z-levels as
before; it would be inefficient to add something in the middle of the list. For
now it's perhaps easiest to create a new list from background, floor, etc. in
the order they are to be painted at every frame.

The view package will have to be implemented before anything will be shown on
screen now... This package should use CurrentDisplay to interface with Java2D.

Renamed KeyCode to KeyPress and updated all references so everything in view
and controller could be compiled. Some things in the model will still have to
be renamed/removed to be compilable.