ENH: Add wide_to_long helper function.
ENH: Allow non-int j vals
DOC: Add wide_to_long to release notes.
CLN: expand groupby dispatch whitelist (GH5480)

- Create separate whitelists for SeriesGroupBy and DataFrameGroupBy objects
- Improve groupby whitelist testing
TST: prevent stderr from leaking to console in util.testing
Merge pull request #5644 from y-p/PR_popen_noise_on_error

TST: prevent stderr from leaking to console in util.testing
BLD: remove ISRELEASED tag from setup.py
BUG: repr_html, fix GH5588 for the MultiIndex case
VB: add vbench for truncated repr_html
Merge pull request #5649 from y-p/PR_GH5588_again

BUG: repr_html, fix GH5588 for the MultiIndex case
DOC: minor changes in .apply section
DOC: SQL to pandas comparison (#4524)
TST: Always define fd in util/testing
DOC: cookbook update
DOC: Series.rename picking up the wrong docstring
PERF: performance regression in frame/apply (GH5654)
Merge pull request #5656 from jreback/apply_perf

PERF: performance regression in frame/apply (GH5654)
API: change _is_copy to is_copy attribute on pandas objects GH(5650)
Merge pull request #5658 from jreback/is_copy

API: change _is_copy to is_copy attribute on pandas objects GH(5650)
Merge pull request #5615 from gjreda/master

DOC: SQL to pandas comparison (#4524)