title: Programmatically send to front/back elements created from interface builder
body: <p>In interface builder, there are layout options to send to back or send to front any elements such as <code>UIButton</code>, <code>UIImage</code>, <code>UILabel</code> etc...</p>
  
  <p>Now, I would like to do the same at runtime, programmatically.</p>
  
  <p>Is there an easy way to do that?</p>
  
  <p>I do not want to create different views, just update the z-axis.</p>