Merge branch 'release/0.5.4' into develop
Add log4cxx
Divided jubatus and jubatus_core
Removed workaround
Remove google-glog
Add check_result to apr, apr-util, log4cxx
Use --regexp-library=re2
Merge pull request #24 from jubatus/add-log4cxx

Update dependency for 0.6.0
bump version
Merge branch 'release/0.6.0'