title: How to find root UIViewController
body: <p>I have a view that is <code>UIViewController</code> (root) that handles ads and a <code>UINavigationController</code>. In that UINavigationController I have typical layers of controllers. In my custom settings table view controller, I have a button to contact me for support. When the user clicks this button I create a <code>MFMailComposeViewController</code> and would like to present it. I can't present it from the settings table view as it will be underneath my ads, so I need to reference the root view and present it from there. I've tried <code>self.parentViewController.parentViewController</code> where self is the settings table view, but that doesn't work. How should I reference this. It seems like a bad design to have to reference the root view directly and pass it to the settings view.</p>