Adds some debugging output in LearnerState and ElectionContext
Updated the contributor list.
Removes looping over all instances in config when joining in ClusterJoin

This loop happens in parallel in ClusterState now.
Adds output of Paxos instance in StateTransitionLogger
Fixes issues with conversation handling, driven by cluster forming failures

Adds proper message header copying in places where it was missing, leading to
 mixup of conversations
Failed proposals will now keep the original conversation id header