Merge changes made in Gnus trunk.

Merge changes made in Gnus trunk.

nnimap.el: Implement partial IMAP article fetch.
nnimap.el: Have nnimap not update the infos if it can't get info from the server.
Implement functions for showing the complete articles.
gnus-int.el (gnus-open-server): Don't query whether to go offline -- just do it.
gnus-art.el (gnus-mime-delete-part): Fix plural for "byte" when there isn't a single byte.
nndoc.el (nndoc-type-alist): Move mime-parts after mbox.  Suggested by Jay Berkenbilt.
mm-decode.el (mm-save-part): Allow saving to other directories the normal Emacs way.
gnus-html.el (gnus-html-rescale-image): Use our defalias gnus-window-inside-pixel-edges.
gnus-srvr.el (gnus-server-copy-server): Add documentation.
gnus.texi (Using IMAP): Document the new nnimap.
nnimap.el (nnimap-wait-for-response): Search further when we're not using streaming.
gnus-int.el (gnus-check-server): Say what the error was when opening failed.
nnheader.el (nnheader-get-report-string): New function.
gnus-int.el (gnus-check-server): Use report-string.
nnimap.el (nnimap-open-connection): Add more error reporting when nnimap fails early.
gnus-start.el (gnus-get-unread-articles): Don't try to open failed servers twice.
nnimap.el (nnimap-wait-for-response): Reversed logic in the nnimap-streaming test.
gnus-art.el: Removed CTAN button stuff, which I don't think is very relevant any more.
Remove NoCeM support, since nobody seems to use it any more.
Remove earcon and gnus-audio.
gnus.el (gnus): Silence gnus-load message.
gnus-group.el (gnus-read-ephemeral-bug-group): Add the bug email address to the To list for easier response.
gnus.texi (Connecting to an IMAP Server): Show how to use as primary method instead of secondary.