Merge branch 'release/0.5.0'
Remove dependency to javassist
Fix error handler
Check nil value
Fix condition
Fix size of elements in tuple
Add get_proxy_status
Merge pull request #18 from jubatus/no-javassist

No javassist
Merge pull request #19 from rimms/add_get_proxy_status_no-javassist

Add get proxy status
bump version
Merge branch 'release/0.5.1'
Add cluster name getter and setter.