title: UIActivityViewController. How to customize it?
body: <p>I would like to create a <code>UIActivityViewController</code> in my iPad application but I can't find anything on Google because it's a new view implemented only in iOS 6.
  <code>UIActivityView</code> is a view that appears when a user tap, for example, the Share button inside Photos App.
  A set of activities is presented by an activity view controller (Send via email, Share on facebook, print ecc...).
  Each activity is represented by an icon and a title that appears below the icon.
  Now I would like to custom the items inside the view but I can't find how to do it?
  Any ideas?</p>