title: jQuery sortable swap elements instead insert
body: <p>I'm a beginner in jQuery and I can't found a solution: I'm using <a href="http://jqueryui.com/sortable/" rel="nofollow">Sortable</a> with a table.
  But the default re-ordering method isn't good for me: I don't want insert the dragged item - I want swap the dragged item and the "current" item (where the mouse pointer is).</p>
  
  <pre><code> $(".timetable").sortable({
       items: "td.ora",
       sort: function(event,ui) {
              // what should I write here?
       });
  </code></pre>
  
  <p>I think should overwrite the <code>sort</code> event but I don't know how.</p>