Startup order independence

[javache]

Make the different applications a little bit less dependent from booting in the right order, especially re boxxy and count-von-count.

Idea: keep a state of each Boxxy, whether it is offline or online. If boxxy is offline and a message needs to be sent, first try sending the config to that boxxy. If succesful, mark it as being online. When a boxxy is online and a message fails to be delivered, mark it as offline and restart the procedure.

[jaspervdj]

Not closing because there's still a problem left: one lagging boxxy (e.g., 30s timeout) will result in later boxxies being contacted 30s later. Fix by adding some paralllelism.