Moves #perform_moves to Piece class from Board
Updates Board file with previous commit
Adds Board#won? #draw? and #winner methods
Adds Game#play which depends on unwritten method #take_turn
Adds Game#get_starting_piece method
Adds Game#get_move_sequence and finishes Game#take_turn
Fixes bug in Board#won?
Shows selected piece. Fixes bug in Piece#perform jump
Adds ability to run as script