title: editButtonItem Does Not Work
body: <p>I have a table view inside a UIViewController with editing enabled for deleting rows. Swiping from the right lets me delete rows and I have the edit button on the navigation bar but it doesn't actually do anything except switch from saying Edit to Done.</p>
  
  <p>Here is how I'm creating my table view.</p>
  
  <pre><code>override func viewWillAppear(animated: Bool) {
      for view in self.view.subviews {
          view.removeFromSuperview()
      }
  
      if sharedCart.shoppingCart.isEmpty {
          self.navigationItem.rightBarButtonItem = nil
  
          isEmptyLabel = UILabel(frame: CGRectMake(self.view.frame.width / 2, self.view.frame.height / 2, self.view.frame.width, self.view.frame.height))
          isEmptyLabel.center = self.view.center
          isEmptyLabel.text = "Your cart is empty."
          isEmptyLabel.textAlignment = .Center
          isEmptyLabel.textColor = UIColor.whiteColor()
          isEmptyLabel.font = UIFont(name: "Helvetica-Light", size: 20.0)
  
          self.view.addSubview(isEmptyLabel)
      } else {
          isEmptyLabel.removeFromSuperview()
          total = 0
  
          let editItem = self.editButtonItem()
          self.navigationItem.rightBarButtonItem = editItem
  
          tableView = UITableView(frame: self.view.frame, style: .Grouped)
          tableView.delegate = self
          tableView.dataSource = self
          tableView.backgroundColor = UIColor.clearColor()
          tableView.contentInset = UIEdgeInsetsMake(44, 0, 0, 0)
  
          tableView.registerNib(UINib(nibName: "CartCell", bundle: nil), forCellReuseIdentifier: "passCartCell")
          tableView.registerNib(UINib(nibName: "CartFooterView", bundle: nil), forHeaderFooterViewReuseIdentifier: "cartFooter")
  
          self.view.addSubview(tableView)
  }
  </code></pre>
  
  <p>And I use these methods for editing.</p>
  
  <pre><code>func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -&gt; Bool {
      return true
  }
  
  func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
      if editingStyle == .Delete {
          sharedCart.shoppingCart.removeAtIndex(indexPath.row)
  
          self.viewWillAppear(true)
      }
  }
  </code></pre>