title: UIImagePickerController conflicts with AVCaptureSession video preview
body: <p>I have a <code>AVCaptureVideoPreviewLayer</code> and a <code>AVCaptureSession</code> to display a video preview on screen.</p>
  
  <p>Separately, I have a <code>UIImagePickerController</code> to capture pictures (using <code>UIImagePickerControllerOriginalImage</code>).</p>
  
  <p>My problem is that when I take a picture with the <code>UIImagePickerController</code>, the <code>AVCaptureSession</code> video preview freezes.</p>
  
  <p>How can prevent the video preview from freezing when I take a picture with the <code>UIImagePickerController</code>?</p>