removes 'result' property from Result and adds 'isDraw' property
fixes getReachableSquares and getSquaresBetween in Board
adds Coords require, corrects reference to getPiece and _isPawnShape in Move
fixes call to getReachableSquares in Position
adds NO_MOVES type and changes description to say colour name instead of player name in Result
corrects references to Result methods in Game
adds tests for Board
adds basic mate test in Game tests