Give other modules the chance to hook in once addthis variable is available

The Facebook share link does not open in a popup window by Addthis and instead a full new window is opened. This is a known problem by AddThis.

In order to overcome it, we added a JavascriptEvent just after the AddThis library is loaded, like this:

// addthis.js
        ...
        function(data, textStatus) {
          addthis.init();
          // Give the chance to other scripts to hook into the addthis variable.
          $(document).trigger('addthis.init', addthis);
        }

In a custom module we bound to the event and fixed the Facebook button's click event (thanks Michael Lablue):

$(document).bind('addthis.init', function(event, addthis) {
    addthis.addEventListener('addthis.ready', function () {
      $('.addthis_toolbox > .addthis_button_facebook')
        .each(function (i, o) {
          o.onclick = function () {
            return addthis_sendto('facebook');
          }
        });
    });
  });