The notmuch mail client

I've intentionally put the most interesting pieces of notmuch into
what I think is a clean and well-documented library interface. I'm
hoping that people will take the code and integrate it into lots of
things I haven't imagined yet. (And integration with dovecot is
definitely something I hadn't imagined.)

Things that I have imagined are a web-based client, and using notmuch
to get good archives of mailing lists. (The fact that mailman's
default archiver, pipermail breaks threads at arbitrary boundaries
likes months has driven me crazy for years.)

-Carl