text: (function($)
  {
      $.Redactor.prototype.bufferbuttons = function()
      {
          return {
              init: function()
              {
                  var undo = this.button.addFirst('undo', 'Undo');
                  var redo = this.button.addAfter('undo', 'redo', 'Redo');
   
                  this.button.addCallback(undo, this.buffer.undo);
                  this.button.addCallback(redo, this.buffer.redo);
              }
          };
      };
  })(jQuery);