Support for IDN domain names

[yusefren]

IDN domain names should be supported
i❤️.ws is valid and working domain
بريد@موقع.شبكة should be valid email address

[troyhunt]

Hey @yusefren, thanks very much for adding this. I've just committed 2 failing tests for this in 6944aa8.

That said (and for anyone that wants to take a stab at implementing this), we're talking about extremely rare edge cases here in terms of the email addresses I see in data breaches. I suspect that anyone attempting to use one of these addresses on most sites would find them rejected and I'd be surprised if they were in broad use. By all means, implement this idea just make sure it doesn't hit the performance of parsing out the most common stuff.