title: Adjust UIPopoverController position after resize
body: <p>I have a <code>UIPopoverController</code> containing a <code>UITableView</code>.  The popover is resized in its view controller's <code>-viewDidAppear</code> function to fit the contents of the table.  While the popover resizes properly, its arrow is usually no longer pointing at the original <code>CGRect</code>.  Is there a way to force the popover to reposition itself after a resize so that its arrow is pointing at its intended target?</p>
  
  <p><b>EDIT:</b> I can't set the size of the popover in <code>-viewDidLoad</code> since the table view does not load its data until <code>-viewDidAppear</code> is called, and as a result I do not know what size the popover should be until then.  In addition, I resize the popover when one of the table view cells is clicked to display another view and this also results in the arrow no longer pointing at its intended target.</p>