add slow log
polish
add latency log in mr
add retry in mr write
add timestamp type option in client side
add slow log in coprocessor
add total read/transaction count in mr
polish log
reset lock expiration between retry
set default cutoff in ThemisCpStatistics
remove themis.timestamp.type to avoid setting timestamp by config option
polish slow operation logs
polish the comment and log for filter
add comment for secondary index table load
fix bug when get/scan the whole family
1. for get/scan, avoid include unneccessary lock in ThemisCpUtil.removeNotRequiredLockColumns
2. for scan:
   2.1 use dataScan to decide the locks in ThemisScanObserver
   2.2 in ThemisCpUtil.constructLockAndWriteScan, avoid the whole lock family is overwrite by following data column
add comment to ThemisCpUtil.prepareScan
use byte match to implement ColumnUtil.containPreservedCharacter
set cluster name firstly before construct themis client zk path
polish log in ThemisScanObserver.next
fix bug when set client side lock ttl
1. fix bug in LockCleaner.constructLocks to set client side lock ttl;
2. check lock expired firstly in transaction.prewriteRowWithLockClean