Adds Game class, HumanPlayer class, HumanPlayer input methods.
Adds Game#make_move and Game#play. Fully functioning game.
Adds unicode symbols for chess pieces.
Adds checker board. Centers pieces on alternating background colors.
Refactors all files and creates chess.rb which requires all other files and starts up the script.
Adds border to board, displays captured pieces.
Adds Pawn promotion, game logic for castling.