Allow disconnected/offline startup

[uglybugger]

No, not via magic pixie dust or the NSA's QUANTUM gadgetry; merely that we should at least allow applications to launch even when they can't connect to a bus endpoint.

It might be nice to allow commands and events to be queued for later transmission but that's a separate issue - I don't really have an opinion yet as to whether that's a responsibility for the bus or for the app. Either way, it's not what this issue is about.