title: Resize tableview in form sheet on iPad when keyboard is shown
body: <p>I'm having difficulties resizing a tableview, and scrolling to the active textfield, when the keyboard appears, when the view is presented modally in a form sheet on an iPad. It works fine on iPhone, since I don't have to take the offset of the form sheet view into account - I can just change the bottom contentInset of the tableview to be the same as the keyboard height. This doesn't work on iPad, however, since the form sheet, and thus its tableview, doesn't occupy the entire screen.</p>
  
  <p>What's the best way to calculate how much the new bottom contentInset of the tableview should be?</p>