title: Change icon on click jstree
body: <p>I have this code using jstree plugin.</p>
  
  <pre><code>$(".gems-tree").on('changed.jstree' , function( event , data ){
    console.log("folder clicked");
  });
  </code></pre>
  
  <p>And it works, but now i want to change the icon from the folder to close to open, is there a way to achive this?</p>
  
  <p><strong>NOTE</strong> </p>
  
  <p>Already try with         <code>data.node.state.opened = true</code> just to see if the folder icon change but not.</p>