1) Re-implemente 64-bit unique tracker id by composed of user configured id salt and current process pid.
2) Add UDP unicast livesync function with config livesync.cluster.batch_unicast,
   for details to see opentracker.conf.sample.
3) Re-indent source codes, by OSX command 'indent -br -lp -i2 -nfbs -di1 -npsl -nut'.