[sup-talk] Ignore killed messages in U screen

[Edward Z. Yang]

Excerpts from William Morgan's message of Thu Sep 03 14:47:19 -0400 2009:
> I'm not sure how I feel about this patch. The semantics of being killed
> are very tied to the inbox. I'm reluctant to start spreading them to
> other types of buffers.

The reason why I request this is because I have a distinction between
unread messages in my inbox and unread messages not in my inbox and
unread messages that are killed.  The 1st is for messages that I
should read (or at least ack), the second is for mailing list messages
and the third is for "I don't actually ever want to see this again,
no really".

Cheers,
Edward