Returns a string representation of this object. if `include_functions` is true, it will also toString() the methods of this object. By default only prints the attributes.
function(include_functions) {
      var s = [];
      $.each(this, function(k, v) {
        if (!_isFunction(v) || include_functions) {
          s.push('"' + k + '": ' + v.toString());
        }
      });
      return "Sammy.Object: {" + s.join(',') + "}";
    }