- Added smtpd.ErrNotExist to make detecting missing message easier
- Return 404 instead of 500 when requesting a non-extistant message
- More REST unit tests
- Add new configuration option [datastore]mailbox.message.cap
- Modify filestore to enforce message cap if value > 0
- Filestore unit tests for message cap when enabled & disabled
- Change to DataStore.Mailbox.NewMessage() interface to allow error
return