TST7337: Disallow use of dateutil tzfile objects whose filename contains '.tar.gz'.
TST7337: Fix test failures on windows.

Avoid constructing dateutil timezones explicitly because of filename issue.
Use dateutil.tz.tzutc() to construct UTC timezone instead of
dateutil.tz.gettz('UTC')
Update docs to reflect this.
Tidy up examples in the timezones section of the docs.
BUG: Bug in multi-index slicing with a step in a sliced level (GH7400)
Add test for conversion between dateutil.tz.tzutc() and dateutil.tz.gettz('UTC')
Merge pull request #7404 from jreback/mi_indexing

BUG: mi indexing bugs (GH7399,GH7400)
BUG/OUTPUT: fix repring of MI nat

Fix neg indexers in datetimeindex
Merge pull request #7362 from ahlmss/windows_tests

TST7337: Fix test failures on windows.
Merge pull request #7410 from cpcloud/nat-index-first-take-7406

BUG: fix repring of nat multiindex and fix neg indexing in datetimeindex
TST7337: Fix more tests in windows
Merge pull request #7414 from ahlmss/tst7337_again

TST7337: Fix more tests in windows
BUG/DTYPES: preserve bools in convert_objects
Merge pull request #7416 from cpcloud/convert-bools-fix-7126

BUG/DTYPES: preserve bools in convert_objects
FIX value_counts should skip NaT #7423
add tests for nanops
BUG: DatetimeIndex.insert doesnt preserve name and tz
BUG: Offset.apply dont preserve time
Merge pull request #7427 from toddrjen/nantest

add unit tests for nanops
Merge pull request #7386 from sinhrks/insert_fix

BUG: Revisit DatetimeIndex.insert doesnt preserve name and tz
PERF: Series.transform speedups (GH6496)
TST: skip tests in test_nanops.py on older scipy (related GH7427)