GitLab

* refine plot

* use warnings

* refine  logic

* revert 'move to compat.py'

* use json instead of repr/eval for pandas_categorical

* fix json dumps with numpy data

* add more test cases

* add compat.py

* unify types

* range/xrange -> range_

* move argc_ to compat.py; add is_numeric error type

* use simplejson for json

* move json to compat.py

* move pandas to compat.py

* move sklearn to compat.py

* remove unused function

* fix 'unify types'

* argc_ (lambda -> def)