Improves JMenuBar creation in the MainFrame

src/main/java/de/tu_darmstadt/tk/SmartHomeNetworkSim/view/MainFrame.java

@@ -77,7 +77,8 @@ public class MainFrame extends JFrame {
 		}
 		
 		JMenuBar menuBar = new JMenuBar();
-		getContentPane().add(menuBar, BorderLayout.NORTH);
+		super.setJMenuBar(menuBar);
+		//getContentPane().add(menuBar, BorderLayout.NORTH);
 		/*
 		JMenuItem mntmOptions = new JMenuItem("Options");
 		mntmOptions.setHorizontalAlignment(SwingConstants.LEFT);