update rdsn: bug fix of json decode/encode; logging when set/del/clear app envs; change backup policy path on zookeeper (#73)

scripts: not start collector in onebox by default; not exit -1 but exit 0 when test fail; update rdsn (#72)

collector: do not send email when email address is not provided; start collector in onebox; improve config to support collector (#70)

replication: updata rdsn; fix brief_stat_mapper;  add manual_compact.disabled env to disable and cancel manual compaction; refactor pegasus_manual_compact.sh (#66)

pegasus_server: improve rocksdb options under PREFER_WRITE usage scenario to avoid flush and compaction peek (#62)

 *: update rdsn; add pegasus_event_listener; add some counters; fix run.sh; limit kill_test log size (#56)

* automatically execute manual compact by set envs.
* add unit test for pegasus server.