Log Message:
Changes 0.2.3:
* Sieve filter tool: finished implementing basic functionality. It is not
  quite ready yet, but it is available for those willing to experiment
  with it (needs --with-unfinished-features config to compile). Also
  includes man page.
* Vacation extension now inhibits replies to messages from sender listed
  in :addresses, thus preventing replies to one of the user's other known
  addresses.
* Vacation extension: implemented the (draft) vacation-seconds extension.
  This also adds min/max period configuration settings. Refer to
  doc/vacation.txt for configuration information.
* ManageSieve: fixed bug in UTF-8 checking of string values. This is done
  by discarding the original implementation and migrating to the Dovecot
  API's UTF-8 functionality.
* Sieve command line tools now avoid initializing the mail store unless
  necessary. This prevents sievec and sieve-dump from failing when
  executed by root for example.
* Enotify extension: fixed inappropriate return type in mailto URI parse
  function, also fixing ARM compiler warning.
* Vacation extension: fixed handling of sendmail errors. It produced an
  additional confusing success message in case of error.
* Removed header MIME-decoding to fix erroneous address parsing. Applies to
  address test and vacation command.
* Fixed segfault bug in extension configuration, triggered when unknown
  extension is mentioned in sieve_extensions setting.