~
~ manually merged: https://github.com/zhuchenwang/cluster2/commit/7ec35c020b86635455bb6641ee42928f48c09ad6#commitcomment-4670675
https://github.com/zhuchenwang/cluster2/commit/7ec35c020b86635455bb6641ee42928f48c09ad6#commitcomment-4670675
Merge pull request #60 from inexplicable/cluster3

https://github.com/zhuchenwang/cluster2/commit/7ec35c020b86635455bb6641ee42928f48c09ad6#commitcomment-4670675