add NAS Conjugate Gradient benchmark
fix profile worker bug
fix np.add, np.multiply, ... can not work for a sparse and a dense
matrix bug
add np.linalg.norm function into buildins
Merge branch 'master' of github.com:spartan-array/spartan

Conflicts:
	spartan/expr/builtins.py
add mahout naive bayes classification app
fix format
Merge pull request #109 from MaggieQi/master

add NAS Conjugate Gradient benchmark and naive bayes
Merge pull request #110 from EasonLiao/master

add svd using lanczos method
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.
fix some codes in the tests (cholesky and conj_gradient)
Merge branch 'master' of github.com:spartan-array/spartan
modify test_cg
fix some codes in the test
add mahout Alternating Least Squares Collaborative Filtering application
fix comments and remove millis
fix comments in als