wrap dkim headers to try to meet 78 character limit, this only wraps in known places to avoid splitting a domain name

Fixes the problem with `SSL_connect returned=1 errno=0 state=error: certificate verify failed` and solves hostname mismatch when use ip address instead of hostname

* Fix for default smtp certificate name

This fixes the defaut smtp certificate file name from smtp.crt to smtp.cert as it is used throughout the postal code.

* Added possibility to use other ports than 80/443

* simplify regex to allow colon anywhere

closes #163

fixes #165