title: Drag and drop from within a NSOutlineView
body: <p>I'm trying to figure out how to implement drag and drop from within a NSOutlineView to itself.</p>
  
  <p>For example, I want the user to be able to reorder and nest and re-nest the items in the NSOutlineView, but I don't need to be able to drag items from any other source (like files or from another view).</p>
  
  <p>All the examples I can find deal with dragging item into the NSOutlineView, not just within itself and seem overly complex.  I assume this is possible.</p>
  
  <p>Can someone point be to some docs that deal with just this case?  Maybe I'm just missing the obvious.</p>