title: What events are available for google.maps.data.addListener?
body: <p>I'm using:</p>
  
  <pre><code>mydatalayer.addListener('click', function(event) { ... });
  mydatalayer.addListener('addfeature', function(event) { ... });
  </code></pre>
  
  <p>without problems.</p>
  
  <p>Now I'm trying to use:</p>
  
  <pre><code>mydatalayer.addListener('dragend', function(event) { ... });
  </code></pre>
  
  <p>but event listener is not fired, although the selected polygon on that layer is correctly dragged on the screen.</p>