Fix wscript for jenerator
Fix gen_version to use the branch name of HEAD
Regenerate clients and servers
Implement graceful exit when zk session expired
fix typo in include guard
Merge pull request #519 from gintenlabo/exit-gracefully-when-zk-session-expired

Implement graceful exit when zookeeper session have expired (fixes #504)
Fix jubatus/util for linking with core
Merge pull request #520 from jubatus/fix-wscript-for-jenerator-version

Fix wscript for generator version

refs #466