Merge changes made in Gnus trunk.
gnus.texi (Archived Messages): Note the default (bug#9552).
message.el (message-indent-citation): Really make sure there's a newline at the end.
nnimap.el (nnimap-parse-flags): Make regexp less prone to overflows. Fix suggested by John Wiegley.
pop3.el (pop3-open-server): Fix +OK end-of-command regexp.
gnus-art.el (gnus-treat-hide-citation): Add doc.
message.el (message-default-send-rename-function): Break out into its own function.
ecomplete.el (ecomplete-display-matches): Revert patch since it doesn't work under XEmacs.
nnimap.el (nnimap-map-port): New function to connect to 993 instead of "imaps" to word around Windows problems.
(nnimap-open-connection-1): Use it.
message.el (message-indent-citation): Revert last change which made `F' not work.