/// <summary>
 /// Start a scene in the collection.
 /// </summary>
 /// <param name="sceneKey">Key to identify scene in collection.</param>
 public void StartScene(string sceneKey)
 {
     //GameScenes has a collection item with this key
     if (GameScenes.ContainsKey(sceneKey))
     {
         //A scene currently running does NOT contain this key
         if (!OpenScenes.ContainsKey(sceneKey))
         {
             var scene = GameScenes[sceneKey];
             scene.Start(Game);
             OpenScenes.Add(sceneKey, scene);
         }
     }
 }