Do not send out-of-order events to StateSupervisor

PaxosStateBridge was erroneously sending unhelpful events to the
StateSupervisor, due to a nextSeq bookkeeping bug. They were dropped
correctly, which is nice, but there were lots of errors, and some extra
work being done. This fixes that error.
Merge pull request #88 from clinedome-work/goodbye-badnewsbears

Do not send out-of-order events to StateSupervisor