title: How to get title from WKInterfaceButton
body: <p>To get title there is function:  </p>
  
  <pre><code>setTitle
  </code></pre>
  
  <p>But how to get title of WKInterfaceButton as string ?</p>
  
  <p>I did not found anything in <a href="https://developer.apple.com/library/prerelease/ios/documentation/WatchKit/Reference/WKInterfaceButton_class/index.html">https://developer.apple.com/library/prerelease/ios/documentation/WatchKit/Reference/WKInterfaceButton_class/index.html</a></p>