Debugged Piece#perform_slide and Piece#perform_jump to update the Board as well as self.pos; added Color attr to Piece and re-implemented Piece#direction to reference :color.
Implement Piece#valid_slides, Piece#valid_jumps, Piece#perform_slide, Piece#perform_jump, Board#move_piece, and Board#display.
Refactor Board#move_piece into Piece#perform_moves\!, Piece#valid_move_seq?, and Piece#perform_moves. Add Board#dup and Piece#dup to support Piece#perform_moves.
Create Game class, Game#play_game, and Game#play_turn, using Piece#perform_moves.
Debug Game#play_game; split into separate files.