DOC: expand the documentation on the xs method
BUG: prevent double plot in Series.hist
DOC: show disallowed/allowed eval syntax
BUG: Fixed a bug in convert_objects for > 2 ndims GH4937
ENH: Add 'is_' method to Index for identity checks

Adds a method that can quickly tell whether something is a view or not
(in the way that actually matters).

CLN: change 'is' check to 'is_' check in 'equals()'
ENH: Added xlsxwriter as an ExcelWriter option.

Added xlsxwriter as an optional writer engine. Issue #4542.
BUG: Fixed a bug in DataFrame/Panel cache insertion and subsequent indexing GH4939
BUG: Fix FrozenNDArray & FrozenList string methods

Plus basic tests (i.e., "Hey! If you pass me unicode I don't fail -
yay!")
DOC: add HTML bad-request cookbook example
ENH: Make ExcelWriter & ExcelFile contextmanagers

both can be used in with statements now. Makes it easier to use with
multiple writers, etc.

Plus touch up the docs on writers and such.
BUG: Fixed a bug with setting invalid or out-of-range values in indexing
     enlargement scenarios (GH4940)
CLN: removed Panel.fillna, replacing within core/generic.py/fillna
TST: Tests for fillna on empty Series (GH4346), thanks @immerrr
BUG: fix incorrect TypeError raise

TypeError was being raised when a ValueError was raised because the
ValueError's message wasn't being converted to a string.
BUG: Fix copy s.t. it always copies index/columns.

Only copies index/columns with `deep=True` on `BlockManager`. Plus some
tests...yay! Change copy to make views of indices.

Requires changing groupby to check whether indices are identical, rather
than comparing with `is`. Plus add tests for name checks through
everything. Also, fixes tests to use `is_()` rather than `is`

CLN: Change groupby to use 'is_' instead
ENH: enable deep copy for sparse Series/Panel
CLN: PEP8 tests/test_index.py and core/index
DOC: remote_data.rst: Fama/French punctuation
API: raise a TypeError on invalid comparison ops on Series (e.g. integer/datetime) (GH4968)
CLN: do not use mutable default arguments