title: Pushing an MFMailComposeViewController onto the navigation stack? Not presented modally
body: <p>I have a table view, and in one of the cells, it says "contact".  Upon selecting this cell, I'd like to push in a MFMailComposeViewController.</p>
  
  <p>I can only seem to present this MFMailComposeViewController modally. What is the problem here?</p>
  
  <p>Thanks!</p>
  
  <p>Relevant code frag:</p>
  
  <pre><code>- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
  
  
      MFMailComposeViewController *controller = [[MFMailComposeViewController alloc] init];
      //*works*//[self.navigationController presentModalViewController:controller animated:YES];
      //*broken*//[self.navigationController pushViewController:controller animated:YES];
  </code></pre>
  
  <p>}</p>
  
  <p>The error that I get is:  " <strong>* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Pushing a navigation controller is not supported'
  *</strong> Call stack at first throw:"</p>
  
  <p>So it looks like I have a navigationController already, and since MFMailComposeViewController is a subclass of UINavigationController, I'm pushing a navController onto another navController?</p>
  
  <p>I want my UI to be consistent, so I want to push a MFMailComposeViewController onto the nav stack rather than present it modally.  </p>