BUG: ujson labels are encoded twice
TST: GH4604, reindexing with a method of 'ffill' gives incorrect results

BUG/CLN: (GH4604) Refactor Series.reindex to core/generic.py allow method= in reindexing
  on a Series to work

API/CLN: GH4604 Infer and downcast dtype if appropriate on ffill/bfill
  this is for consistency when doing: df.reindex().ffill() and df.reindex(method='ffill')

CLN: allow backfill/pad/interpolate to operate on integers (by float conversion)
     provide downcasting back to original dtype where needed core.internals.interpolate

ENH: provide core.index.identical method to compare values and attributes similar to .equals

API: changed back to pre-GH3482 where a reindex with no args will by default copy
Merge pull request #4593 from Komnomnomnom/ujson-slash-happy

BUG: ujson labels are encoded twice
BUG: GH3317 Fix frequency inference to be automatic in a DatetimeIndex if freq is not specified during _ensure_index

PERF: remove automatic downcasting, instead do on-demand via 'downcast=infer'

TST: fix up failing tests

CLN: reindex/fill in internals moved to core/internals/Block/reindex_items_from

PERF: don't automatically downcast with a float block

BUG: GH3317 reverse prior fix in tseries/offsets, to change slightly the multi reindex

TST: identical index tests

BUG: GH4618 provide automatic downcasting on a reindexed with method Series
     (in this case a shifted boolean then filled series)
Merge pull request #4610 from jreback/series_reindex

CLN: refactor Series.reindex to core/generic
ENH: Keep original traceback in DataFrame.apply

When "raise <exception instance>" is used inside a try/except block, the
original stacktrace (containing the code path that raised the original
exception).  This makes debugging difficult since all we know is that an error
occured when `frame._apply_standard` attempted to call the provided function.
Preserve the original stacktrace by using "raise" instead of "raise <exception
instance>".  This facilitates debugginb by allowing us to see where (in the
provided callable) the exception occured.

Added mention of this change in release notes
Merge pull request #4549 from bburan-galenea/bburan-galenea/apply_exception_traceback

ENH/API: Keep original traceback in DataFrame.apply
BUG: Fix selection with ``ix/loc`` and non_unique selectors (GH4619)
Merge pull request #4622 from jreback/ix_issue

BUG: Fix selection with ``ix/loc`` and non_unique selectors (GH4619)
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