[Pan-users] (Small) feature request: couple more filtering options

[NM]

The rules/filtering system in Pan is quite complex, but sadly it lacks
one important configuration option: you cannot really choose on what
field to operate, besides "from" and "message-id". 

Several times already, when a group was flooded by usenet bullies, I
found it was'nt enough; the bastards were forging email addresses and
changing all the time. Even message-Id is not enough as it is either in
some case not generated by the server, or cannot be really singled out
to a single source of junk.

On the other hand, being able to filter based on the "Path" line would
allow to single out crap usenet providers, and "posting-host" would
allow to ignore stupid fucks, even only temporarily.

If I have time I might even work on this, who knows.