* lisp/gnus.el (gnus-version-number): Update to 6.12.20

* lisp/gnus.el (gnus-version-number): Update to 6.12.20

*lisp/gnus-agent.el, lisp/gnus-bbdb.el, lisp/gnus-msg.el,
lisp/gnus-offline.el, lisp/gnus-ofsetup.el, lisp/gnus-score.el,
lisp/gnus-util.el, lisp/gnus.el, lisp/message.el,
lisp/nnheader.el, lisp/nnmail.el, lisp/pop3-fma.el, lisp/pop3.el:
Sync up with nana-gnus-1_13_12.

* lisp/gnus-util.el (gnus-write-active-file): Copy from Gnus 5.8.2.

* lisp/gnus-score.el (gnus-enter-score-words-into-hashtb): Ignore
invalid character error.

* lisp/gnus-msg.el (gnus-post-method): Do not duplicate methods.

* lisp/gnus-agent.el (gnus-agent-expire): Sync up with Gnus
5.8.2.

* lisp/gnus-bbdb.el (gnus-bbdb/split-mail-1): Fix bug for last
change.

* lisp/gnus-bbdb.el (gnus-bbdb/split-mail): New implementation,
and supports crosspost.
(gnus-bbdb/split-mail-1): New function.

* lisp/message.el (message-yank-add-new-references): New option
value `message-id-only'.
(message-yank-original): Likewise.
(message-list-references-add-position): New user option.
(message-list-references): When
`message-list-references-add-position' is integer value, the order
of designate number message-ids is kept.

* lisp/gnus-util.el (TopLevel): Do not require `rmail'.

* lisp/gnus-msg.el (gnus-bug): Do not send bug report to
`bugs@gnus.org'.

* lisp/gnus-agent.el (gnus-agent-toggle-plugged): Don't change
buffer modified status.

* lisp/nnheader.el (TopLevel): Require `poem'.

* lisp/nnmail.el (nnmail-move-inbox): Do not change current
buffer. And change require timing of password.

* lisp/nnmail.el (nnmail-split-it): Match whole word for getting
group name with `\N'.

* lisp/gnus-ofsetup.el (gnus-ofsetup-read-pop-account): Add prefix
"po:" to POP file name.

* lisp/nnmail.el (nnmail-movemail-program-pop-password-required):
New variable.
(nnmail-exec-movemail-program): Require password, when needed.
(TopLevel): Remove autoload cookie.
(nnmail-pop3-movemail): Require `pop3'.

* lisp/gnus-ofsetup.el (gnus-ofsetup-read-pop-account): Fix bug.
(gnus-setup-for-offline): Generate nnmail-pop-password-required's
value.

* lisp/gnus-offline.el: Do not use pop3-fma.el. (Thank you,
Tsukamoto Tetsuo <czkmt@remus.dti.ne.jp>)

* lisp/gnus-ofsetup.el (gnus-offline-setting-file): Change to
"~/.nana-gnus-offline.el".
(gnus-ofsetup-read-from-minibuffer): New function.
(gnus-ofsetup-completing-read-symbol): Ditto.
(gnus-ofsetup-read-pop-account): Ditto.
(gnus-setup-for-offline): Refine.

* lisp/nnmail.el (nnmail-get-spool-files): Fix bug in latest changes.
(nnmail-pop3-movemail): Ditto.

Sync up with Nana-gnus 6.13.12.