Log Message:
Update to 0.9.9.6:

** 0.9.9.6

*** mu

    - truncate /all/ terms the go beyond xapian's max term length
    - lowercase the domain-part of email addresses in mu cfind (and mu4e), if
      the domain is in ascii
    - give messages without msgids fake-message-ids; this fixes the problem
      where such messages were not found in --include-related queries
    - cleanup of the query parser
    - much improved date parsing
    - support recursive maildirs
    - many fixes in the query parser; there are still a number of
      corner cases though, which probably requires writing a custom
      query parser to fix
    - drop gmime 2.4 support

*** mu4e

    - update the emacs <-> backend protocol; documented in the
      mu-server man page
    - improve saving attachment
    - allow for visiting multiple URIs
    - much improved navigation within messages

    - mug

      - only support gtk+ 3.x

    - mu-guile:

      - more examples; bug fixes