Fixed issue that when go back to start screen, start view doesn't fit

in to the decorator properly.

- Moved start screen view initialization logic into ViewManager.
- When go back to start screen view, a new stage within the start screen
view will be initialized.

#story[1245]

src/main/java/seng302/visualiser/controllers/ServerListController.java

@@ -56,7 +56,6 @@ public class ServerListController implements Initializable, ServerListenerDelega
 
         try {
             ServerListener.getInstance().setDelegate(this);
-            System.out.println("Setting DH");
         } catch (IOException e) {
             logger.warn("Could not start Server Listener Delegate");
         }