[afew] announcing afew, an universal tagging solution with some fancy features

[James Vasile]

I'm tring to figure out how to use afew.  It looks interesting, but
gives me surprising results.

I did `afew --learn spam -- tag:spam` and believe this tells afew that
all the messages matching tag:spam should be classified as spam.  But if
that is right, why would `afew -c spam -- tag:spam` then show me a bunch
of messages that are tagged spam by notmuch but not classified spam by
afew?

How do I train afew when I correct it's mistakes?  Is that what `afew
update` is for?  What does "update the reference category" mean?

Thanks much,
James