Add error messages and XLANG markers.
(clean_text)  Rename _clean_text to reflect external use.
"make siteconfig" will allow some sitewide configuration values
  to be changed without reinstalling.
Rephrase.
Reword some error messages.
Minor clarification.
Warn that the whoami_owner setting should not contain the
address of the list.
Add list-subscribe to list-unsubscribe and the list's address as
addresses that should not be subscribed to a list.  Thanks to
Brock Rozen.
Clarify.
(subscribe)  Prevent a variety of reserved addresses from being
  subscribed to a mailing list.
  Suggested by Brock Rozen.
(confirm)  Bugfix:  Use the correct address in To: headers of
  confirmation messages.
  Thanks to Jeff Wasilko.
update