Add a test script
Add callback to `listen` method

This mimics `node` core APIs.
Merge pull request #3 from mmalecki/listen-callback

Add `listen` callback
Update README.md

Added documentation pointing out that MX records need to take an array with a priority and a server value in order to work properly.
Merge pull request #5 from mattjay/master

Update README.md
Use the value's connection, falling back to the original response connection
Support encoding PTR messages
Support encoding and decoding AAAA records
Working on v0.9.2
Working on v0.9.3
Throw the correct error
Support more domain labels to correctly encode reverse IPv6 lookups
Working on v0.9.4
Support IN DS messages
Working on v0.9.5