title: Set contentMode of UIImageView
body: <p>In Obj-C</p>
  
  <p><code>imageView.contentMode = UIViewContentModeScaleAspectFill;</code></p>
  
  <p>would set the contentMode.</p>
  
  <p>Why does </p>
  
  <p><code>imageView.contentMode = UIViewContentModeScaleAspectFill</code></p>
  
  <p>not work in Swift?</p>