Works just like `jQuery.fn.bind()` with a couple noteable differences.  * It binds all events to the application element * All events are bound within the `eventNamespace()` * Events are not actually bound until the application is started with `run()` * callbacks are evaluated within the context of a Sammy.EventContext  See http://code.quirkey.com/sammy/docs/events.html for more info.
function(name, data, callback) {
      var app = this;
      // build the callback
      // if the arity is 2, callback is the second argument
      if (typeof callback == 'undefined') { callback = data; }
      var listener_callback =  function() {
        // pull off the context from the arguments to the callback
        var e, context, data;
        e       = arguments[0];
        data    = arguments[1];
        if (data && data.context) {
          context = data.context;
          delete data.context;
        } else {
          context = new app.context_prototype(app, 'bind', e.type, data, e.target);
        }
        e.cleaned_type = e.type.replace(app.eventNamespace(), '');
        callback.apply(context, [e, data]);
      };

      // it could be that the app element doesnt exist yet
      // so attach to the listeners array and then run()
      // will actually bind the event.
      if (!this.listeners[name]) { this.listeners[name] = []; }
      this.listeners[name].push(listener_callback);
      if (this.isRunning()) {
        // if the app is running
        // *actually* bind the event to the app element
        this._listen(name, listener_callback);
      }
      return this;
    }