DOC: release notes (GH5443)
BUG: bug in `o_datetime when passed a np.nan or integer datelike and a format string (GH5863)
Merge pull request #5864 from jreback/to_datetime

BUG: bug in to_datetime when passed a np.nan or integer datelike and a format string (GH5863)
BLD: enhancements to print_versions.py
DOC: updated compare w r
BLD: make util/print_versions.py standlone as well
Merge pull request #5866 from chappers/r-compare

DOC: Flesh out the R comparison section of docs (GH3980)
Merge pull request #5842 from jvns/patch-1

Add pandas cookbook to tutorials (for #5837)
BLD/DOC: explain how to print_versions() sans repo in CONTRIBUTING.md
DOC: tweaks to CONTRIBUTING.md
DOC: show the Panel.reindex API change in v0.13.0.txt (GH5867)
BLD: fixup setup.py, initialize pipe variable to None
Merge pull request #5868 from y-p/PR_setup_pipe

BLD: fixup setup.py, initialize pipe variable to None
BUG: Bug in groupby dtype conversion with datetimelike (GH5869)
Merge pull request #5870 from jreback/groupby_ts

BUG: Bug in groupby dtype conversion with datetimelike (GH5869)
BLD: python3 unicode issue in print_versions
DOC: r match function
Update comparison_with_r.rst

rm index
Update comparison_with_r.rst
BUG: Regresssion in handling of empty Series as indexers to Series  (GH5877)