Merge changes made in Gnus master

Merge changes made in Gnus master

2012-09-05 Julien Danjou <julien@danjou.info>
* gnus-srvr.el (gnus-server-open-server): Don't message on failure:
  this hide the real reason with a message giving absolutely no hint.

2012-09-05 Lars Ingebrigtsen <larsi@gnus.org>
* gnus-group.el (gnus-group-mark-article-read): Propagate the read mark
  to the backend (bug#11804).
* message.el (message-insert-newsgroups): Don't insert newsgroup
  duplicates (bug#12275).

2012-09-05 John Wiegley <johnw@newartisans.com>
* gnus.el (gnus-expand-group-parameters): Allow regexp substitutions in
  sieve rules.

2012-09-05 Jan Tatarik <jan.tatarik@gmail.com>
* gnus-score.el (gnus-score-decode-text-parts): Use #' for the local
  function.
* gnus-logic.el (gnus-advanced-body): Allow scoring on decoded bodies.
* gnus-score.el (gnus-score-decode-text-parts): Ditto.

2012-09-05 Magnus Henoch <magnus.henoch@gmail.com>
* nnmaildir.el: Make nnmaildir understand and write maildir flags.
  That is, rename files from "unique:2," to "unique:2,S" for "seen", etc.
  This should make nnmaildir more usable with offlineimap.