Add babou logo to bootstrap template.
Disable event-filter for now.
Major changes to bridge architecture.

* Bridge now uses packets internally, messages externally. Messages remain unchanged.
* Packets carry a subscriber name; which is either a named worker on LocalTransport, or named "foreign"
  if it came from a socket.
* Bridge dispatches messages to subscribers.
* Broadcast now wraps message inside a packet for delivery.

* Named subscribers in the local transport are NOT guaranteed unique. I plan to fix this by
  having `bridge#Subscribe()` assign and return a [reasonably] unique ID.
Tracker server now uses pubsub bridge.
Rename #Send & #ASend
Documentation & rename 'inbox' for clarity.
Use channel as buffering/sync mechanism for outbox [again].
Merge branch 'feature/refactor-bridge' into develop