COMPAT: provide numpy compat with 1.7 for numeric methods when calling like: np.prod(obj)
        as numpy is now passing extra args to the pandas methods!
CLN: refactor all numeric type stats methods to core/generic.py
     from the object level modules (e.g. mean/sum/min/max....)
CLN: refactor cum methods to core/generic.py
CLN: make_stat_function for numeric methods in core/generic.py
Merge pull request #5034 from jreback/numpy_compat

BUG/CLN: numpy compat with pandas numeric functions and cln of same (GH4435)