Make nnimap treat \Deleted articles as \Read articles

* nnimap.el (nnimap-update-info): Treat \Deleted articles as \Read
articles.
Don't do Gcc handling if Gnus isn't running

* gnus-msg.el (gnus-inews-insert-gcc): Don't insert Gcc headers if Gnus
isn't running, because Gnus will probably not know how to handle the
Gcc header (bug#11941).
Update copyright notices for 2013