refactor
Merge pull request #29 from fengjingchao/dev

change name
merge and refactor
merge master
Merge pull request #30 from xiangli-cmu/dev

refactor
change setRId to setRepicaId, add something to recvPrepareReply()
Merge pull request #31 from yifan-gu/dev

change setRId to setRepicaId, add something to recvPrepareReply()
prototype for recovery and clear counts before sending message