FED-85: message processors loop on leader flag set by zookeeper
FED-85: set leader flag on election; LeaderSelector methods synchronized
FED-85: set leader selector auto-requeue; add flag for manually disabling leader nodes in debug mode
FED-85: Fixed message cleanup to be scheduled and canceled when a node takes leadership and loses it, respectively.
Merge pull request #34 from janrain/FED-85-zk-leader-selector-fix

The leader election looks much cleaner, lets give it to QA.