mu is a set of utilities to deal with Maildirs, specifically,
indexing and searching.

- mu-index - recursively scans a collection of email messages, and
stores information found in a database.

- mu-find - searches for messages based on some search criteria.

- mu-msginfo - gives information (such as subject, sender, message
body) for a certain message file

- mu-mkmdir - creates a new Maildir

mu uses libgmime2 to parse the message, and SQLite and Xapian to
store the message data.
