New port dnsdb/dnsdbq.

This is a pure C program that accesses the DNSDB API server at Farsight
Security. An API key is required for operation. The command syntax was
inspired by a python script called dnsdb_query, but significant departure
has occured, largely inspired by a modern understanding of "time fencing"
and a desire for new features such as CSV output and JSON reprocessing.

Sponsored by: Farsight Security, Inc.