Payload full test, with a blackhole broker

Summary:
Tests a more realistic scenario where:

• a payload is received
• events are fully dispatched

We mock the broker to allow to run the test without one.

This bumps the dependency to Keruald Broker from 0.1 to 0.2.

Test Plan: phpunit

Reviewers: dereckson

Projects: Notifications center, Keruald

Differential Revision: http://devcentral.nasqueron.org/D197