Add support for "hosts" aliasing in Zope instances.
Add support for SASL relayhost with mandatory TLS encryption.
Add mandatory TSL + SASL authentication, to not be an open relay.
Wrap postfix commands with proper environment instead of symlink +
source-able script.
Add ipv6 listening support (untested).
Drop non-required main.cf configuration options.
Make postifx instance optional (requires postmaster address to be
provided).
Document and rework smtp-related parameters.
Expose an userhosts hostname for smtp server.
Add diversion support (solution to "prod clone sent mails to real customer").
Use etc/run rather than etc/service, for consistency (if it needs to be
changed, it must be changed for all software types).
Hook into syslog and setup local syslog daemon, with logrotate integration.
Update TODO entries.