title: Adding a closure as target to a UIButton
body: <p>I have a generic control class which needs to set the completion of the button depending on the view controller.Due to that setLeftButtonActionWithClosure function needs to take as parameter a closure which should be set as action to an unbutton.How would it be possible in Swift since we need to pass the function name as String to action: parameter.</p>
  <pre><code>func setLeftButtonActionWithClosure(completion: () -&gt; Void)
  {
      self.leftButton.addTarget(&lt;#target: AnyObject?#&gt;, action: &lt;#Selector#&gt;, forControlEvents: &lt;#UIControlEvents#&gt;)
  }
  </code></pre>