Feature request: to use `hasmail` with a local maildir?

Hello,

I really enjoy using `hasmail` and it is really stable but I would really like to use it with a synced local maildir. I use [`mbsync`](http://isync.sourceforge.net) to sync my mail on my machine and I use `systemd` timers to sync it periodically.

I would like to use `hasmail` to check for new mail on a local `maildir`. The idea is to have a single program that syncs the mail and not having a secondary program that performs another IMAP connection to the server.