function unescape(str) {
    return str.replace(unescapeRe, function($0, $1) {
        switch ($1) {
            case "\\":
            case "":
                return $1;
            default:
                return unescapeMap[$1] || "";
        }
    });
}
Unescapes a string.
@param {string} str String to unescape
@returns {string} Unescaped string
@property {Object.<string,string>} map Special characters map
@ignore