Will bind a single callback function to every event that is already being listened to in the app. This includes all the `APP_EVENTS` as well as any custom events defined with `bind()`.  Used internally for debug logging.
function(callback) {
      var app = this;
      // bind to the APP_EVENTS first
      $.each(this.APP_EVENTS, function(i, e) {
        app.bind(e, callback);
      });
      // next, bind to listener names (only if they dont exist in APP_EVENTS)
      $.each(this.listeners.keys(true), function(i, name) {
        if (app.APP_EVENTS.indexOf(name) == -1) {
          app.bind(name, callback);
        }
      });
      return this;
    }