public function merge($array, $default=true)
    {
        $newarray = array();

        foreach ($array as $key=>$value) {
            $newKey = is_numeric($key) ? $value : $key;
            $newValue = is_numeric($key) ? true : $value;
            $newarray[$newKey] = $newValue;
        }

        $this->_options = array_merge($this->_options, $newarray);

        return $this;
    }