Exotherm - Chess logic begins

Yesterday I got my bot to connect to the FICS. Today I started writing its chess logic. It can now parse a style12 line into an object representing the game state. That class has a method that executes a given move (without testing legality) and returns the new game state. That'll be necessary for thinking ahead and testing hypothetical moves. Considering en passant, castling, and promotion was pretty finicky, but I think this part works. I also wrote a function to generate the hypothetical move targets for a given piece, again not fully testing legality yet.