util/chrono-sync: In ChronoSync, added publishNextSequenceNumber and use in Chat. Added getSequenceNumber() and make usrseq_ private. This allows us to remove the public pokeData method. We can also make update and logfind private.
util/chrono-sync: In ChronoSync, make the following methods private: processRecoveryInst, processSyncInst, sendRecovery, judgeRecovery, syncTimeout and initialOndata.