added game end screen

also! the new singleton system doesn't work! returning to the main menu creates a second instance of everything, @nick can you fix this please

Assets/Scripts/SceneController.cs

@@ -33,6 +33,15 @@ public class SceneController : MonoBehaviour
         { // if this is the menu
             GameObject.Find("NewGameButton").GetComponent<Button>().onClick.AddListener(NextScene);
         }
+
+        // if this is the last scene
+        if (scene.buildIndex == (SceneManager.sceneCountInBuildSettings - 1)) {
+            GameObject backToMenuButton = GameObject.Find("BackToMenuButton");
+            if (backToMenuButton != null) {
+                backToMenuButton.GetComponent<Button>().onClick.AddListener(delegate{LoadChosenScene(0);});
+                backToMenuButton.SetActive(false);
+            }
+        }
     }
 
     public void NextScene()