Checking wishlist items off

README.org: Some of these wishlist items are done
Better separate triggering for sent/received msgs

lisp/gnorb-gnus.el: (gnorb-gnus-incoming-do-todo) The variable
		    `gnorb-gnus-sending-message-info always holds info
		    about the last sent message. If the trigger process
		    sees that, it assumes we're triggering from that
		    sent message. So blank out
		    `gnorb-gnus-sending-message-info' while we're
		    triggering from an incoming message.
Fix call of key-description

lisp/gnorb-gnus.el: (gnorb-gnus-incoming-do-todo) If we're only
		    returning a single value, we don't need mapconcat,
		    smart guy.