:viewuser filters specifically on zephyr

[broder@mit.edu]

Running :viewuser nelhage currently generates the filter

user-nelhage: ( type ^zephyr$ and filter personal and ( ( direction ^in$ and sender ^nelhage@ATHENA\.MIT\.EDU$ ) or ( direction ^out$ and recipient ^nelhage@ATHENA\.MIT\.EDU$ ) ) ) or ( ( class ^login$ ) and ( sender ^nelhage@ATHENA\.MIT\.EDU$ ) )

It seems like it would be better (and would better support the theory that BarnOwl is more than just a zephyr client) if the filters dropped the type ^zephyr$ constraint, in favor of catching anything with the given sender/recipient.

As it stands, filtering on, say, Jabber messages with a particular user is difficult, because you need to catch messages where the user is both a sender and a recipient.

Nelson notes:

   barnowl / vu / nelhage  17:55  (Is a named type file (120))
       I'd probably take a patch.
[...]
   barnowl / vu / nelhage  17:56  (Bad address (14))
       Preferably one that also updates tab-completion.

[adehnert@mit.edu]

See also #176.