[sync] Improved unescape when opt.unescape_strings = true
https://github.com/einars/js-beautify/commit/b91e6cd324e9d5ccd0d21983bc57208b7a0ec042

+ Add CommonJS export
https://github.com/einars/js-beautify/commit/cfdc29e6560f1973cb782b49e5f54a0c8878e90e
Add -unescapeStrings argument