title: how to dismiss a modal view controller presented as "Form Sheet" when a touch occur outside the form sheet?
body: <p>I have a View Controller (with a UIWebView) i present in Form Sheet style.
  I have to put a "Done" button in the UIToolbar of the view in the View Controller to have it dismissed.
  But, since presenting it in "Form Sheet" style leaves plenty of unused space outside the View Controller's view... I was wandering..
  Is there a way to detect a touch outside the View? in that "grayed out" area?
  Thanks in advance</p>