R1:684d12d5db23

Add an example notification handler to the IRC bot

Summary: Simple notificaiton handler that reads the difx event timeline and
posts notifications to IRC.

Test Plan: Ran it in #phabricator.

Reviewers: btrahan, jungejason

Reviewed By: btrahan

CC: aran, btrahan

Differential Revision: https://secure.phabricator.com/D1337