Board  displays with colorized tiles, self.get_starting_locations added to Piece.
FiniiteMover module working; added module MoveOps
Finished legal_moves method for InfiniteMover
Pawn#legal_moves is working, refactored to eliminate moved_once
Added Board#check? and Board#board_in_check?
Board#checkmate, Tile#add_piece, Tile#remove_piece methods
Working version 1.0; added move_ops.rb
Working Version 1.1 - check & checkmate both working correctly.