Re-enable basic forward functionality
Save raw email
Forward raw email with original envelope
cleanup linter warnings
Get forwarding SMTP options from command-line

Added options:

 --forward-host <host>  SMTP host to forward emails
 --forward-port <port>  SMTP port to forward emails
 --forward-user <user>  SMTP user to forward emails
 --forward-pass <pass>  SMTP password to forward emails
 --forward-secure       Use SMTP SSL to forward emails
Rename "forward" to "relay"
Add documentation