Tagging script for notmuch mail

 The basic task of afew is to provide automatic tagging each time new
 mail is registered with notmuch. In a classic setup, you might call it
 after 'notmuch new' in an offlineimap post sync hook.
 .
 In addition to more elementary features such as adding tags based on
 email headers or maildir folders, handling killed threads and spam, it
 can do some heavy magic in order to /learn/ how to initially tag your
 mails based on their content.
 .
 In move mode, afew will move mails between maildir folders according to
 configurable rules that can contain arbitrary notmuch queries to match
 against any searchable attributes.