Merge pull request #7285 from cpcloud/openpyxl-format-string-fix-7284

BUG/CI/TST: fix format strings
BUG: BoolBlock shouldn't replace truthy values
ENH/TST: add anonymous reading of s3 for public buckets
Merge pull request #7304 from cpcloud/fix-replace-bool-yet-again-7140

BUG: replace() alters unrelated values
BUG/TST: should skip openpyxl before testing version compat
Merge pull request #7281 from cpcloud/public-s3-7246

ENH/TST: add anonymous reading of s3 for public buckets
Merge pull request #7311 from cpcloud/openpyxl-format-string-fix-7284

BUG/TST: should skip openpyxl before testing version compat
make more nanops work with complex numbers
support axis=None for nanmedian
make nanops work when ndim==1 and axis==0
fix nanops when used with pandas objects
add tests for nanops
implement additional tests for groupby apply methods
simplify groupby's std method
add sem to nanops
add sem to aggregate methods
add sem to groupby
add sem to docs
minor nanops pep8 fixes