Better message in exception when conversion from period to timestamp fails
CLN: Remove core/array.py
Allow importing pandas without setuptools
return explicitly for inplace
FIX: add nbytes property in Categorical
Merge pull request #8406 from sh9189/bbopensrcday2

CLN: Remove core/array.py
Merge pull request #8409 from jacobschaer/issue-8107

Allow importing pandas without setuptools
Merge pull request #8414 from JanSchulz/nbytes_categories

FIX: add nbytes property in Categorical
BUG: Bug in interesection of non-monotonic non-unique indexes (GH8362)
Merge pull request #8405 from sh9189/bbopensrcday

Better message in exception when conversion from period to timestamp fai...
BUG: apply Series mask to aligned new values (GH8387)
BUG: fix panel fillna ignoring axis parameter
added/fixed tests and re-ordered _is_mixed_type check
fill axis defaults to stat axis
implement inplace; simplify a bit
changed ffill and bfill default axis to None
fixed inplace implementation
trying Panel.apply
more apply work
merge in new tests