#12 All mailing software

[B.Tikkanen]

More care has to be taken when making mailing software.
All header, from and etc have to be real data since
this is validated at many servers, causing lost mail if
blocked.

For example, mail from can't be user@somedomain.com if
we send from roquez, from has to be a valid roquez user
(somebody allowed to send via roquez).

Also, right MIME type since this can also cause mails
to be blocked