Add @mhdawson back to the CTC

Now that the CTC has expanded, this PR calls for a vote of the CTC
to reinstate Michael Dawson (@mhdawson) as a full voting member.

Voted on and approved by the CTC on 2016-03-23

PR-URL: https://github.com/nodejs/node/pull/5633


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Alexis Campailla <orangemocha@nodejs.org>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>