Buildbot <-> Taskcluster Bridge

The Buildbot Bridge is a set of services that allow us to schedule jobs in Taskcluster but run them in Buildbot. The Taskcluster Listener listens for pending Taskcluster Tasks and creates BuildRequests for them. The Buildbot Listener listens for Buildbot events for those jobs, and updates the Taskcluster Tasks accordingly. The Reflector reclaims Taskcluster Tasks and polls for changes that can't be detected by listening for Taskcluster on Buildbot events. It is awesome :).