Add license header
Unit tests for ByteArrayComparator
Reset the validator after injecting a message
Remove dead test code
Log DNSKEY validation failure at first known location
Simplify code
Remove detection of impossible cases

No DS is already detected as NODATA in the previous key finding phase
and will result in a null-KeyEntry. A corresponding DNSKEY will never
be searched.
New tests: DNSKEYs with unmatched footprint and algorithm are ignored