anchor.diff:  RenderLoop renderLoop;
   ResourceManager resourceManager;
   Juggler juggler;
  -Tween tween;
  +Ship ship;
  +Bullet bullet;
  +
   
   void main() {
     // setup the Stage and RenderLoop
  
positive.code:             ship.movingDown = true;
              break;
        }
          
      });
  
      //Event listener for cursor keyUP events
  
negative.code: //-----------------------------------------------------------------------------
  
  part 'Ship.dart';
  part 'Bullet.dart';
  
  //-----------------------------------------------------------------------------
  
  