title: UITableViewCellSelectionStyleNone whilst still showing checkmark in edit mode
body: <p>I am having issues setting the cell background colour on a grouped table cell when in edit mode. It seems to get the checkmark to appear a selection style has to be set and the only options are UITableViewCellSelectionStyleBlue or UITableViewCellSelectionStyleGray. 
  What I am after is the for the checkmark just to be selected and the cell remain white when it is checked. </p>
  
  <p>You would have thought UITableViewCellSelectionStyleNone would have this behaviour but this stops the checkmark for showing.</p>
  
  <p><img src="https://i.stack.imgur.com/dvC98.jpg" alt="UITableViewCellSelectionStyleNone no checkmark shows when selected"></p>
  
  <p>I have tried to use setSelectedBackgroundView. This would work if the cell style was not grouped but as it is the round corners do not get drawn.</p>
  
  <p><img src="https://i.stack.imgur.com/6zpN3.jpg" alt="Custom background view problem with corners."></p>
  
  <p>The properties for the cell above are </p>
  
  <pre><code>    cell.selectionStyle = UITableViewCellSelectionStyleGray;
      cell.backgroundView = [self tableViewCellRowBackground];
  </code></pre>
  
  <p>Where tableViewCellRowBackground is a UIView with orange background.
  The editMode is the built in iOS table edit mode with the following properties set on the table</p>
  
  <pre><code>    self.tblFiles.allowsSelectionDuringEditing=YES;
      self.tblFiles.allowsMultipleSelectionDuringEditing = YES;
  </code></pre>
  
  <p>Any ideas?</p>