Ensure that we can get a commit number from git

Currently, git describe fails with "fatal: No names found, cannot describe anything."
Merge pull request #5520 from invisibleroads/patch-2

Ensure that we can get a commit number from git
BUG: Bug in getitem with a multi-index and iloc (GH5528)
Merge pull request #5529 from jreback/iloc_mi

BUG: Bug in getitem with a multi-index and iloc (GH5528)
CLN: PEP8 cleanup
Merge pull request #5038 from alefnula/pep8

CLN: PEP8 cleanup
CLN: More autopep8
TST: correctly predict locale setability

Don't join the lang and encoding when performing the trial set, because

    locale.setlocale(locale.LC_ALL, ('it_CH', 'utf-8'))

succeeds, but

    locale.setlocale(locale.LC_ALL, 'it_CH.utf-8')

throws locale.Error.
Merge pull request #5538 from neirbowj/fbsd_failing_tests

TST: correctly predict locale setability
TST: fix cumcount test on 32-bit env
Merge pull request #5540 from gdraps/cumcount-test-fix

TST: fix cumcount test on 32-bit env
BUG: Bug in delitem on a Series (GH5542)
Merge pull request #5544 from jreback/series_del

BUG: Bug in delitem on a Series (GH5542)
DOC: mention new to_clipboard/paste into excel capability
Merge pull request #5548 from y-p/doc_toclipboard

DOC: mention new to_clipboard/paste into excel capability in release docs
StataWriter: Replace non-isalnum characters in variable names by _ instead of integral represantation of replaced character. Eliminate duplicates created by replacement.