UTF-8 (cyrillic) email validation 2-nd try

I added more cases in tests to make shure it works according to rfc https://tools.ietf.org/html/rfc2822 
I can't imagine how it can brake BC. It just converts UTF symbols in domain to ASCII the way the browser does.
And also makes an assumption, that characters allowed in login are the same that in domain (whitch is pretty close to reality).