title: Foursquare API : How to mention a friend in a foursquare checkin or comment?
body: <p>Via the foursquare website and I'm assuming the foursquare iPhone app you can now mention friends in the checkin shout or comments of a checkin. The friend is then notified of the mention.</p>
  
  <p>How do we markup the shout/comment for sending to the checkins/add or addcomment endpoints?</p>