Add empty-mix test for clustering
Merge pull request #743 from jubatus/fix-plugin-path

Fix plugin path
Merge pull request #751 from gintenlabo/fix-segv-on-distributed-gmm-clustering

Allow empty data for gmm::batch (fixes #750)
Fix driver test for new mixable
Add  #include <string> to mixer.hpp
Add type method to mixers
Merge pull request #749 from jubatus/fix-634

Use absolute path for the values of get_status (fix #634)
Merge pull request #771 from jubatus/fix-713

Output message when plugin loaded: fixes #713