Use jubatus_core instead of jubatus
Fix implementation of key_manager
Add unit test for weight_manager
Fix weight_manager for new version of classifier

Add version
Use double for couter instead of unsigned int
Remove debug log
Add version_number to output
Fix recommender type structure
Merge pull request #11 from jubatus/support-core

Support core
Update requirements
Merge branch 'release/0.6.0'