//add restart button
JButton scramble = new JButton("Restart");
scramble.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
Layout layout = vv.getGraphLayout();
layout.initialize();
Relaxer relaxer = vv.getModel().getRelaxer();
if(relaxer != null) {
relaxer.stop();
relaxer.prerelax();
relaxer.relax();