add support for Internationalized Domain Names (IDN)

[karentamrazyan]

web sniffer should support internationalized domain names (IDNs) in queries, e.g. for domains like:

• 英伟达.中国 ("xn--cpq367j69h.xn--fiqs8s" in encoded form)
• fußball.de (fussball.de)
• президент.рф ("xn--d1abbgf6aiiy.xn--p1ai" in encoded form)

tags: IDN, IDNA, Punycode