Static-frame

Performance enhancements to ``Frame.pivot()``, ``Frame.iter_group()``, and ``Frame.iter_group_items()``.

``Frame.pivot()`` ``func`` parameter can now be set to ``None`` to perform no aggregation.

Extended ``Series.from_overlay()`` and ``Frame.from_overlay()`` to support ``func`` and ``fill_value`` arguments; ``func`` can be used to optionally specify what elements are available for assignment in overlay.

Extended ``via_fill_value()`` interfaces to implement ``__getitem__`` and ``loc`` selection interfaces on :obj:`Series` and :obj:`Frame` for selections that potentially contain new labels filled with the fill value.

Added ``NPY`` and ``NPZ`` interfaces for creating NPY and NPZ archvies from arrays and ``Frame`` components.

Added ``index_constructors`` argument to ``IndexHierarchy.from_product()``

Added ``index_constructor`` argument to ``Index.level_add()``, ``IndexHierarchy.level_add()``, and ``Frame.relabel_level_add()``.

Added ``index_constructor``, ``columns_constructor`` arguments to ``Frame.relabel()``.

Added ``Series.to_frame_he()``.

Added ``index``, ``index_constructor``, ``columns``, ``columns_constructor`` arguments to ``Series.to_frame()``, ``Series.to_frame_go()``, ``Series.to_frame_he()``.

Improvement to ``Frame.from_concat`` to avoid creating one-element indices from ``Series`` when an index is provided along the appropriate axis.

Added ``index_constructor`` argument to ``Series.relabel()``.

Added ``index_constructor`` argument to ``Series.from_concat()``.

Added ``index`` argument to ``Series.from_pandas()``.

Added ``index`` and ``columns`` argument to ``Frame.from_pandas()``.

Improvement to ``Index`` initialization to raise ``ErrorInitIndex`` if given a single string as ``labels``.

Set operations on labels of different ``datetime64`` units now raise an ``Exception``.

Performance enhancements to ``Frame.from_npy`` and ``Frame.from_npz``.

Added ``Frame.to_pickle()``, ``Frame.from_pickle()``.

Added ``index_constructor``, ``columns_constructor`` to ``Frame.from_concat``.

Fixed issue in ``Frame.insert_after()``, ``Frame.insert_before()``, ``Series.insert_after()``, ``Series.insert_before()`` with negative ``ILoc`` labels.

Added ``Frame.from_npy_mmap``; removed ``memory_map`` option from ``Frame.from_npy``.

Performance enhancements to ``Frame.from_npy`` and ``Frame.from_npz``.