re-enable worker rpc profiling.
merge to resolve conflicts.
fix kmeans correctness error. add parameter for initializing center points
some changes on kmeans based on code review
Merge pull request #113 from EasonLiao/fix_kmeans

Fixed correctness issue. Add parameter for initializing center points
rephrase the comments.
Merge pull request #112 from EasonLiao/rpc_profile

re-enable worker rpc profiling.
Merge branch 'master' of github.com:spartan-array/spartan