Don't validate emails with regex

[sethgrid]

Check out:
http://play.golang.org/p/fKwLaT3gY4

It shows many valid email addresses as invalid. See

https://en.wikipedia.org/wiki/Email_address#Valid_email_addresses
https://davidcel.is/posts/stop-validating-email-addresses-with-regex/
Related:
http://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address

If you really want to use regular expressions (which is not Go's strong suit), just check if there is something before and after an @.

[aliuygur]

Thank you. I will refactor.

[aliuygur]

fixed d428c94