Discovers bug in Board#initialize & Board#default_board.
Fixes bugs in Board#initialize & Board#default_board. Adds unicode characters to Board and Piece classes. Adds Piece#render.Discovers bug in Board#default_board.
Fixes bug in Board#default_board.
Fixes bug in Board#default_board. Adds Piece#on_opposite_side?. Adds Piece#maybe_promote.
Adds stylistic change to Board#render.
Fixes Board#move. Completes Piece#perform_slide. Fixes typo in Piece#move_diffs.
Adds Piece#jump_diffs. Adds Piece#perform_jump.
Changed Piece ivar terminoligy to kinged.