feat: add option parsing
fix: add log
fix: change config file format
feat: make paxos peer for app server
feat: add value type
feat: add call to paxos.Start
fix:serialize value first
checkpoint: test Paxos.Status not work
checkpoint: why paxos lean a value from other in a simple  instruction?
fix: fix bug

1. fix bug in paxos, should initialize value to -1 if not commited.
2. basic new instruction in app server
feat: get doc done.
update RPC interface
add implementation for Min in paxos_impl
add recover/consul.go as recover manager