For heartbeats, correctly track multiple instances of the same worker species
Set heartbeat system-id as a command-line option
Merge branch 'develop' into feature/issue-487-better-worker-identification
heartbeats: added fixes after some integration testing
Rewrote the heartbeat monitoring worker.

  * Added a Redis storage backend.
  * System ID passed to workers via --system-id option
And actually add the changes to the index this time... See last commit msg.
Merge branch 'develop' into feature/issue-487-better-worker-identification
PEP8 and unused import clean ups.
Move heartbeat tests into conventional location.
Update test locations.
Merge branch 'feature/issue-487-better-worker-identification' of github.com:praekelt/vumi into feature/issue-487-better-worker-identification

Conflicts:
	vumi/blinkenlights/heartbeat/tests/test_monitor.py
Clean-up __eq__ and __hash__ implementations slightly.
Return NotImplemented if we don't know how to compare something to a WorkerInstance.
Don't shadow deadline class variable with instance variable unnecessarily.
Use new worker config system
Remove @Manager.calls_manager adaptors from heartbeat/storage.py
Remove unused class variable from heartbeat/monitor.py
Resolve a cyclical dependency issue
Revert back to using @Manager.calls_manager in heartbeats/storage.py
Merge branch 'develop' into feature/issue-487-better-worker-identification