title: how to reload/refresh/reinit DynaTree?
body: <p>When I do  the following </p>
  
  <pre><code>$('#tree').dynatree("option","initAjax",{url:"http://google.com"});
  </code></pre>
  
  <p>I want dynatree to forget about current tree data and reload with new data from the specified  url instead. But I find it does not do that by default.</p>
  
  <p>Thanks.</p>