title: "Will rotate" notification?
body: <p>Is it possible to get a "will rotate" notification on iOS, <strong>before</strong> the rotation animations are executed? Like the <code>UIViewController</code> method <code>willRotateToInterfaceOrientation:duration:</code>.</p>
  
  <p>I know of <code>UIDeviceOrientationDidChangeNotification</code>, but that one appears to be sent <strong>after</strong> the rotation animations are executed.</p>
  
  <p>I'm working in a <code>NSObject</code> subclass, outside of view controllers.</p>
  
  <p>If there is no such notification, I was considering a hack such as adding a "fake" view to the view hierarchy (to the <code>rootViewController</code>'s view?), and override <code>layoutSubviews</code> to send a custom notification. Is there a less hackish alternative?</p>