code: function on(events, callback, context)
    {
      return onListeners( this, events, callback, context, EventNode.Types.Persistent );
    }
docs: Listens for every occurrence of the given events and invokes the callback
  each time any of them are triggered.
  
  @method on
  @memberof Rekord.Eventful#
  @param {String|Array} events -
  The event or events to listen to.
  @param {Function} callback -
  The function to invoke when any of the events are invoked.
  @param {Object} [context] -
  The value of `this` when the callback is invoked. If not specified, the
  reference of the object this function exists on will be `this`.
  @return {Function} -
  A function to invoke to stop listening to all of the events given.
   
  Listens for every occurrence of the given events and invokes the callback
  each time any of them are triggered.
  
  @method $on
  @memberof Rekord.Eventful$#
  @param {String|Array} events -
  The event or events to listen to.
  @param {Function} callback -
  The function to invoke when any of the events are invoked.
  @param {Object} [context] -
  The value of `this` when the callback is invoked. If not specified, the
  reference of the object this function exists on will be `this`.
  @return {Function} -
  A function to invoke to stop listening to all of the events given.