title: MKMapView not staying rotated
body: <p>Easy to reproduce:
  - create a new project
  - put an MKMapView on the screen
  - try to rotate it with 2 fingers</p>
  
  <p>It rotates a little and stops, and when you release the fingers, it goes back to the original position.</p>
  
  <p>How do I make it stay rotated?
  And rotate as much as I want?</p>
  
  <p>I'm using latest iOS (8.something), iPhone 6 simulator and Swift.</p>