mail/archiveopteryx: Update to latest git

archiveopteryx has not received an official release in many years and
many fixes have been accumulating. I have traditionally published the
git version under the mail/archiveopteryhx-devel port, but many
improvements have happened that aox users should be getting by default.
I'm working with upstream to get a new release finally made.

While here, correct the LICENSE which is actually PostgreSQL, not MIT.