Implementation of Stata 13 (format 117) support
Updated docs
Fixed docstring of read_stata
Removed unused imports
Fixed some bugs in Stata format 117 parsing
Added unit testing for Stata 13 format
BUG: prevent double plot in Series.hist
Merge pull request #4662 from PKEuS/master

Added Stata 13 support
DOC: v0.13.0 for stata enhancement
DOC: issue reference for 4298
DOC: expand the documentation on the xs method
DOC: fix read_stata formatting typo
Merge pull request #4921 from cpcloud/mi-doc-blurb

DOC: expand the documentation on the xs method
Merge pull request #4113 from cpcloud/double-fig-series-hist-by-fix

BUG: make sure fig is not doubled when passing by to series.hist
DOC: show disallowed/allowed eval syntax
Merge pull request #4922 from cpcloud/eval-syntax-docs

DOC: show disallowed eval syntax
BUG: Fixed a bug in convert_objects for > 2 ndims GH4937
Merge pull request #4938 from jreback/panel_convert

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()'
Merge pull request #4909 from jtratner/add-is_-method-to-index

ENH: Add 'is_' method to Index for identity checks
ENH: Added xlsxwriter as an ExcelWriter option.

Added xlsxwriter as an optional writer engine. Issue #4542.
Merge pull request #4857 from jmcnamara/enh_xlsxwriter2

ENH: Added xlsxwriter as an ExcelWriter option.
BUG: Fixed a bug in DataFrame/Panel cache insertion and subsequent indexing GH4939
Merge pull request #4942 from jreback/index_cache

BUG: Fixed a bug in DataFrame/Panel cache insertion and subsequent indexing GH4939