code on Nostr: query: support until for kind query plans (William Casarin) ndb: some query docs ...

query: support until for kind query plans (William Casarin)
ndb: some query docs (William Casarin)

pushed to nostrdb:refs/heads/master
http://git.jb55.com/nostrdb/commit/8540083e16ffda95077fd44165d2476a569edd62.html