Default is AlphaBeta.
Updated ActionListener for UserChooserFrame so that selecting from the list (or typing a new name and pressing RETURN) also triggers the action.
Added the player and computer algorithm names to the title bar e.g. "Bob vs. Alpha-Beta".
- Added support for the player model inside Referee.java; high scores should now persist over a single execution of the program.
- Refactored PlayerModel.java to support game logging. All games are now logged so that we can track overall progress.
- Added scaffolding to allow saving and importing of PlayerModel.java. It is not yet functional, but it will be with two function implementations and then the appropriate calls.
