Static-frame

Fixed issue in using ``Frame.extend`` with zero-length ``Frame``.

Implemented ``Frame.isin`` on ``TypeBlocks``.

Implemented ``Frame.clip`` on ``TypeBlocks``.

Series.from_element`` now works correctly with tuples.

``Batch`` element handling now avoids diagonal formations; ``Batch.apply()`` now handles elements correctly.

``dtypes`` parameters can now be provided with ``dict_values`` instances.

``Frame.to_parquet``, ``Frame.to_arrow`` now convert ``np.datetime64`` units to nanosecond if not supported by PyArrow.

Bus`` now exposes ``max_persist`` parameter to define the maximum number of loaded ``Frame`` retained by the ``Bus``.

Added ``len()`` to ``via_str`` interfaces.

``Frame.iter_element`` now takes an ``axis`` argument to determine element order, where 0 is row major, 1 is column major.

Silenced ``NaturalNameWarning`` via ``tables`` in ``StoreHDF5``.

``StoreSQLite`` will now re-write, rather than update, a file path where an SQLite DB already exists.

Improved handling for iterating zero-sized ``Frame``.

Improved type detection when performing operations on ``Frame.iter_element`` iterators.

``Frame.shift()`` ``file_value`` parameter is now key-word argument only.

``Frame.roll()`` ``include_index``, ``include_columns`` is now key-word argument only.

Extended application of binary equality operators to permit comparison with arrays of single elements.

Refined application of binary equality operators to permit comparison with strings or elements that are not sequences.