title: "Missing argument for parameter 'style' in call" error in creating system UIBarButtonItem
body: <p>I don't understand why the compiler is asking for an argument to the style parameter in this system-style UIBarButtonItem initializer--it does not have that parameter in the first place. Help? Is this a bug with Swift?</p>
  
  <pre><code>class ExpensesViewController: UIViewController {
  
      lazy var newExpenseBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Add, target: self, action: Selector("newExpenseBarButtonItemTapped:"))
  
      func newExpenseBarButtonItemTapped() {
  
      }
  
  }
  </code></pre>