if the library or daemon is compiled with address sanitizer, objects in
freelists are poisoned to detect use-after-recycle errors
it is not currently used in the library, as there are no freelists

refs #33

refs #16

this is Unbound's 'forward-zone' on steroids

the library is able to resolve query in stub mode (no referral chasing,
zone cut lookup) if asked to
validator turns off for stub queries, validating stub is NYI

thanks to Pieter Lexis and Peter van Dijk from PowerDNS for discovering this.

the RFC4035 M < S < N stands if the S isn’t after the last name in the zone, this is indicated by M > N, proving that the next of the last name is the first name; if the S is after M, then it proves it’s non-existence

thanks to Pieter Lexis and Peter van Dijk from PowerDNS for discovering this!

resolved() returns true if current query is resolved (i.e. authoritative)
final() returns true if current query is resolved and is not a subrequest (has no parent)

as the libknot packet interface disallows out-of-order packet
writes, authority and additional records must be written after
the answer is complete; records in the rr arrays will be written to final answer during finalization

this yields much better contrast in this situation, where
one country overshadows the rest on a linear scale