TST: GH4312, assignment with iloc/loc and an dtype change
BUG: Fix assignment with iloc/loc involving a dtype change in an existing column (GH4312)
TST: add tests/test_generic.py

API/CLN: Refactor rename methods to core/generic.py; fixes Series.rename for (GH4605), and adds rename
   with the same signature for ``Panel``

API/CLN: Refactor Series.copy to core/generic.py; removes the order argument from Series.copy (inconsistent)
Merge pull request #4624 from jreback/astype_iloc2

API/CLN: setitem in Series now consistent with DataFrame
Merge pull request #4627 from jreback/rename_consist

API/CLN: make rename and copy consistent across NDFrame
Merge branch 'master' of https://github.com/timmie/pandas
added documentationon pandas.datetime
added a better desciption