function traverse(node)
	{
		callback(node);

		for (var i = 0; i < node.children.length; i++)
		{
			traverse(node.children[i]);
		}
	}
Traverse the whole tree view and call the callback method.

The callback method receives the object attached to the tree and the depth.

@method traverse
@param {Function} callback Callback function(treeNode)