this can be used as an intermediate 'patch' util there is a validation
system in place.

the extra check is to verify that the domain part of a correctly
formatted email address is existing and in use. this will not at all
stop spammers since they can use bogus emails with valid domain parts

Lukas: Minor formatting changes.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>