Add Vert.x based TCP protocol and endpoint.
Add Vert.x HTTP endpoint.
Remove copycat-netty project.
Remove key/value store example.
Fix NPE in DefaultProtocolInstance.
Remove core logging.properties.
Add various tests.
Remove ping request/response, replcaed by empty sync request/response.
Document cluster and endpoint types.
Add public context methods for reading the current cluster leader.
Return the cluster leader from Vert.x endpoints.
Fix NPE in candidate.
Clean up leader code and use atomic operations for checking replica connection status.
Refactor state machine API snapshot and command return types.
Add annotated state machine helper class.
Update protocol type documentation.
Add serializer documentation.
Document core types.
Update README documentation.