sent to all sessions.
(get-last-text): Say that this relies on all texts being written
	in chronological order.
(set-client-version): This call can only be used once per session.  It
	will return client-is-crazy if used twice.
(get-client-version): This was called "get-client-name".
(mark-text): Bogus example fixed.
(unmark-text): Bogus example fixed.
(lookup-z-name): The want-pers and want-confs arguments were
	swapped in the function header.
(set-info): Document that lyskomd 1.9.0 erroneously returned
	text-zero if MOTD was 0.