title: FancyTree has Empty Nodes
body: <p>I have the folowing code pretty much straight from the demo:</p>
  
  <pre><code>$("#treetable").fancytree({
  extensions: ["table"],
  table: {
  indentation: 20,  // indent 20px per node level
  nodeColumnIdx: 0  // render the node title into the 1st column
  },
  source: {url: "productTree.json"},
  rendercolumns: function(e, data) {
  var node = data.node,
  $tdList = $(node.tr).find("&gt;td");
  // (index #0 is rendered by fancytree - see above)
  $tdList.eq(1).text(node.modeldet);
  $tdList.eq(2).text(node.key);
  $tdList.eq(3).text(node.inclusion);
   }
  });
  </code></pre>
  
  <p>And this is the JSON:</p>
  
  <pre><code>[
  {"title": "All Products", "key": "*", "folder": true, "children": [
      {"title": "Smart Product 1", "key": "Smart", "inclusion": "Mandatory", "folder": true, "children": [
          {"title": "Simple A", "key": "One Time Fee", "modeldet": "0-50 Units"},
          {"title": "Simple B", "key": "Per Unit or Metered Usage", "modeldet": "More than 50 Units"}
      ]},
      {"title": "Simple A", "key": "One Time Fee", "inclusion": "Mandatory"},
      {"title": "Simple B", "key": "Per Unit or Metered Usage", "inclusion": "Mandatory"},
      {"title": "Simple C", "key": "Reservation", "inclusion": "Optional", "extraClasses": "my-extra-class" },
      {"title": "Simple D", "key": "Service or Recurring Fee", "inclusion": "Optional", "extraClasses": "my-extra-class" }
  ]}  
  ]
  </code></pre>
  
  <p>The tree renders but the only columns that contain data are the "title" and "key".  The others are blank.</p>