TST/CLN: centralize common validation methods in test_graphics
Merge pull request #7036 from sinhrks/cln_plottest

TST/CLN: centralize common validation methods in test_graphics
BLD: catch additional network error messages
API: update nth to use the _set_selection_from_grouper
     makes first == nth(0) and last = = nth(-1)
DOC: groupby v0.14.0 doc changes
Merge pull request #7044 from jreback/groupby_nth

API: update nth to use the _set_selection_from_grouper makes first==nth(0) and last==nth(-1)
BUG: tz info lost by set_index and reindex
DOC: update groupby/v0.14.0 docs for nth
Merge pull request #7092 from sinhrks/appendtz

BUG: tz info lost by set_index and reindex
DOC: groupby.rst edits
DOC: tiny groupby.rst edit
TYPO: idxmax is maximum, not minimum

Confusing doc typo was momentarily confusing.
Merge pull request #7102 from gruen/master

TYPO: idxmax is maximum, not minimum