[DPP-86] A way to synchronously shutdown a ManagedProcess

[qnikst]

[Imported from JIRA. Reported by Roman Gonzalez @roman) as DPP-86 on 2013-12-12 22:48:33]
Would it be possible to have a shutdown on ManagedProcess that is not Asynchronous. I want to ensure Supervisor children are dying before I exit, probably a variant where we can decide a Shutdown Timeout?