title: Facebook Built-in Like action callback
body: <p>Facebook recently introduced the "Built-in Like" as a built-in Open Graph action (see <a href="https://developers.facebook.com/blog/post/2012/06/20/bringing-like-to-mobile/" rel="nofollow">blogpost</a> and <a href="https://developers.facebook.com/docs/opengraph/actions/builtin/likes/" rel="nofollow">documentation</a>). I would like to implement this functionality in my iOS App and be able to listen to the event, when the user completes the like action (similarly to using <a href="https://developers.facebook.com/docs/reference/javascript/FB.Event.subscribe/" rel="nofollow">FB.Event.subscribe</a> in JavaScript). Is this posible and how would you accomplish this?</p>