add SETEX command for KV
Merge pull request #99 from holys/develop

add SETEX command support for the KV data structure
update config
update bench tool
update protocol handling
update benchmark
add slice for store, optimize leveldb/rocksdb get
set replication config to false default
add reap protocol benchmark
rename to dbbench using ledis
refactor db getslice
add go slice
optimize benchmark

thanks joe
optimize and bugfix TTL, must upgrade manually
add flag upgrade-ttl
update benchmark
bugfix ledis-dbbench