gnus-registry improvements

gnus-registry improvements

[Ted Zlatanov]

If you use gnus-registry, be aware that I just checked in a major
change.  From now on, the registry will get the full name of a group,
not the short name, and will try to figure out if that group is in
another backend.  You have to turn on
gnus-registry-use-long-group-names for that to happen - otherwise,
you will get the old (short group names no matter what) behavior.

Group names are always stored as full names now, whereas before
spooled groups were stored in their short form.

The registry gets the current command method from either
gnus-command-method (active during splitting) or gnus-newsgroup-name
(active during `B q' operations, it seems).  It compares that command
method to the one implicit in the group name.  If the methods are the
same, the group is OK (note that we don't just check if the server has
a group by that name) and the message (level 9) is

gnus-registry-split-fancy-with-parent stripped group nnimap+mail.lifelogs.com:mail to mail

whereas, if the methods differ, the group is set to nil (thus,
gnus-registry-split-fancy-with-parent hands off the split to the next
element) and the message (level 5) is

gnus-registry-split-fancy-with-parent ignored foreign group nnimap+mail.lifelogs.com:ion

This is a big change, and I need everyone who uses the registry to try
turning gnus-registry-use-long-group-names on and see how well it
works.  Those who want to keep the old settings, just leave that
variable nil and you should be fine.

Once this feature is stable, I will work on queueing messages to a
foreign group and moving them later.  To this end, I have these
questions:

- how can I get the article number of an article that was just
  spooled?

- can I modify an incoming article (in order to insert a
  Gnus-Delayed-Move-To header)?  If so, how would I process that
  header later?

Please report any gnus-registry bugs you observe.  Thanks!

Ted