Optimization of ``Bus.items()``, ``Bus.values``, ``Bus.iter_element()``, and ``Bus.iter_element_items()`` when ``max_persist`` is greater than one.
Added ``Yarn.iter_element()``, ``Yarn.iter_element_items()``.
Added ``Yarn.drop[]``
Added ``Yarn.reindex()``, ``Yarn.relabel_flat()``, ``Yarn.relabel_level_add()``, ``Yarn.relabel_level_drop()``, ``Yarn.rehierarch()``.
Added ``Bus.unpersist()``, ``Yarn.unpersist()``, and ``Quilt.unpersist()``.
Improvements to standard string representation of ``Quilt``.
Added ``is_month_start()``, ``is_month_end()``, ``is_year_start()``, ``is_year_end()``, ``is_quarter_start()``, ``is_quarter_end()`` to ``via_dt`` interfaces.
Added ``hour``, ``minute``, ``second`` properties to ``via_dt`` interfaces.
Improved implementation of ``weekday()``, added ``quarter()`` to ``via_dt`` interfaces.
Fixed issue when using ``iter_window_*`` methods on two-dimensional containers where the opposite axis is not a default index constructor.
Fixed issue when selecting rows from ``Frame`` with 0-length columns.