rev. 25

Added the Xboard commands "undo", "remove", "hint", and "new".
All Interfaces now properly quit, not leaving the engine thread alive.
Invalid argument(s) on startup is exception handled better.
Created the beginnings to a Configure window.
Other minor improvements.

rev. 24

Imported the project from Sourceforge.
Added promotion letters to AnimatsChess's command output.
Added underpromotion options for both the engine and the player in Swing.
Other minor changes.