TODO

- Rate Limiting for outbound mail (there's a branch for this but it's incomplete)
- Milter support
- Ability to modify the body of email (e.g add a banner)
- Create a config file for each of the core shipping configs, so people have something as a baseline
- IMAP server (long shot for now)
- Plugins to copy from Qpsmtpd:
  - bogus_bounce (checks bounces have one recipient and no return-path)
  - dspam
  - greylisting
  - karma?
  - virus/*

Outbound improvements
 - Provide better command line tools for manipulating/inspecting the queue
 - Add the ability to force a run on a specific queue file or destination domain
 - Make retry times configurable (handle RFC requirements for 5 days and DSN queued warnings)
 - Limit concurrency by domain
 - Disable deliveries for a domain
 - Pool connections by domain/MX