v4.0 start working on paxos
v4.1 restructure paxos and serverview
modify paxosManager interface
v4.2 create proposalNumPair
v4.3 write up prepare, accept of paxos
v4.4 implement instant view version of paxos
v4.5 tmp version, improve logic in paxos, receive response from current view
v4.5.1 improve paxos, new view is decided in phase2 responders
v4.6 paxos, incredental increase server is ok
4.7 change paxos select value method
v5.0 paxos test complete
seems work now