Deal with Supervision properly

(Missing Feature, Investigate , Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Scalability
Summary: I haven't been worrying much about Supervision until we have moved to a scalable architecture, but once we do, there's no excuse not to get this right.
Go through the system, and think about supervision. Look at each supervisor, and make a formal decision about what it’s supervisorStrategy should be. (The default might actually be okay, but we shouldn’t assume that.)