BUG: unwanted conversions of timedelta dtypes when in a mixed datetimelike frame (GH7778)
TST: tests for internals/as_matrix() for all dtypes (including categoricals)
Merge pull request #7779 from jreback/td

BUG: unwanted conversions of timedelta dtypes when in a mixed datetimelike frame (GH7778)
Docs: Categorical docs fixups.
Merge pull request #7783 from lexual/docs_categorical_tidyup

Docs: Categorical docs fixups.
BUG: Bug in Series 0-division with a float and integer operand dtypes  (GH7785)
Merge pull request #7786 from jreback/div

BUG: Bug in Series 0-division with a float and integer operand dtypes  (GH7785)
Raise exception on non-unique column index in to_hdf for fixed format.

Fixes #7761.