fixed inconsistency in ObjectController setting VX and VY of gameobject

GameProject/src/controller/ObjectController.java

@@ -56,7 +56,7 @@ public abstract class ObjectController {
   public void applySpeedVector() {
     double ts = this.getPlayground().getTimestep();
     this.setX(this.getX() + this.getVX() * ts);
-    gameObject.setY(this.getY() + this.getVY() * ts);
+    this.setY(this.getY() + this.getVY() * ts);
   }