[broker] handle reception errors and re-attempts
Created originally on Bitbucket by cdevienne (Christophe de Vienne)
If an actor misses a envelope ACK, it will resend the envelope fragment. Currently this will raise an error, which forces the actor the restart the whole emission, and the Process will remain stalled.
If receiving a fragment is made idempotent (with maybe some conditions like is the Process in error), we would have to deal with less problems.