Adding "mail2Fax"-command
- this "mail2fax" contains a simple extension to send mails to the capisuite
  which sends the email-contene out as fax
- it works for Exim4, by setting up a dedicated subdomain handling the fax-
  feature (fax.example.com)
- the user-part of the emails are the fax-numers to send to (045214@fax.example.com)
- the "csfax_helper" handles plaintext-emails and multipart-emails (only the 1st
  attachment, which is no PGP-signature, will be faxed)