title: Get main storyboard in universal app
body: <p>Trying my hand at a universal project, I'd like to load a vc by identifier from storyboard.  Is there a way to avoid an explicit check of the idiom when accessing the storyboard.</p>
  
  <p>This ugly code works....</p>
  
  <pre><code>UIStoryboard *storyboard;
  
  if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
      storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPad" bundle:nil];
  }
  else {
      storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:nil];
  }
  
  UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"MyViewController"];
  </code></pre>
  
  <p>But yuck.  The string literal main storyboard is hard enough to look at (not sure why the project cannot save a main storyboard setting so that apps can say [UIStoryboard mainStoryboard];) but the explicit idiom check is a bridge too far.</p>
  
  <p>Is there any hidden intelligence (comparable to "@2x" image suffixes supporting retina displays) that could clean this code?</p>