anchor.diff:  
     StageXL.Vector _newDirection;
   
  +  final StageXL.Vector _zeroVector = new StageXL.Vector.zero();
  +
     final StageXL.Vector _zeroOneVector = new StageXL.Vector(0, 1);
   
     final StageXL.Vector _oneZeroVector = new StageXL.Vector(1, 0);
  
positive.code:   /**
     * Slows down the sprite's movement.
     */
    slowDown() {
      if (_speedUnderEqualMinSpeed() && _accelerationDirection == -1) {
        _accelerationDirection = _NO_ACCELERATION_DIRECTION;
      } else {
  
negative.code:   /**
     * Removes the sprite from the world and juggler.
     */
    void removeFromWorld() {
      alive = false;
      _context.game.world.removeChild(this);
      if (isMovable) {
  