Merge pull request #70 from MaggieQi/master

fix test_serialization nosetests error
Bug fixed of test_fio.py.
Use sklearn from pypi.
psutil.phymem_usage has been deprecated.
Use psutil.virtual_memory.
Merge pull request #71 from fegin/master

Bugs and warnings fixed.
Add logistic regression and ridge regression examples based on SGD.
Make SGD as an independent class.
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Comments
Fixed DeprecationWarning: using a non-integer number ....
Merge pull request #72 from fegin/master

Add logistic regression and ridge regression examples based on SGD.
Merge pull request #73 from fegin/master

Fixed DeprecationWarning: using a non-integer number ....
Merge branch 'master' of github.com:spartan-array/spartan
change some var name in test_pagerank