Add stats collector
Add doc and end of line
Arc lint fixes
Fix line width
Merge branch 'master' of https://github.com/facebook/rocksdb
Add java docs for StatsCollector constructor and StatsCollectorCallback thread safety
Merge pull request #183 from ankgup87/master

[Java] Merge pull request #183 --- Add statistics collector utility

Summary:
1. Add statistics collector which collects statistics periodically at a period specified by caller.
2. Added unit-test for StatsCollector

make rocksdbjava
make test

Reviewers: haobo, yhchiang, sdong, dhruba, rsumbaly, zzbennett, swapnilghike
Reviewed By: yhchiang
CC: leveldb

Differential Revision: https://reviews.facebook.net/19215