[Pine-info] Select multiple folders by status, rule

[Josef Dalcolmo]

I'd often like to search for messages in multiple folders by status, 
keyword or rule as well as text. Currently it does not seem to be possible 
to select by status or rule on the collection level. But it would be very 
useful to be able to search for messages with a particular flag or keyword 
in multiple folders at the same time.

- Josef