Tidy up exported/non-exported fields
Clean up some code-review issues
Hoist WriteMsg calls up
Extract checkInFlightQueries method
Simplified algorithm in checkInFlightQueries()
forgot to remove 'dns'
Replace hard-coded 4 with const for channel size
Support returning AAAA records from delegated DNS queries
Extract interface util functions to their own file
Wait for interface in main
Changed local domain handling

 1. The local domain is now ".weave.local", which is safer from TLD
 pollution
 2. If the name given for an IP isn't a subdomain of the local domain,
 ignore it
Replaced ad-hoc printf with log levels