Static-frame

Fixed flaw in ``IndexLevel`` for handling of zero-length levels.

Fixed flaw in ``TypeBlocks.iloc`` that caused an undesirable reference cycle.

IndexHierarchy`` set operations will now delegate ``Index`` types when they are equivalent between operands at corresponding depth levels.

``Frame.from_concat`` now delegates returned index input index name, type, ``IndexHierarchy`` contained types, if aligned on all indices per axis.

Fixed issue when calling ``relabel_add_level()`` from a ``FrameGO``.

Extended functionality of ``HLoc`` selections in ``IndexHierarchy`` to properly handle selection lists, Boolean arrays, and nested ``ILoc`` selections.

Corrected issue in ``Frame.from_concat`` whereby, when given inputs with ``IndexHierarchy``, ``IndexHierarchy`` were not returned.

Extended ``name`` propagation to applications of binary operators where an opperand is a scalar.

Binary operators now work with ``Frame`` and same-shaped NumPy arrays.

Extended support for step arguments in ``loc`` interfaces.

Implemented ``Frame.join_left``, ``Frame.join_right``, ``Frame.join_inner``, and ``Frame.join_outer``.

Implemented ``Frame.insert_before``, ``Frame.insert_after``.

Implemented ``Series.insert_before``, ``Series.insert_after``.

``IndexHierarchy.from_labels`` now enforces all labels to have the same depth.

Fixed issue where, when passing an array to ``Frame.from_records``, the ``name`` parameter is not passed to the constructor.

Implemented ``equals()`` methods on all containers.

Added defensive check against assigning a Pandas Series to a FrameGO as an unlabeled iterator.

Added proper handling of types multiple-inherited from ``str`` (or any other type) and ``Enum``.

Implemented support for operator overloading of addition and multiplication on string dtypes.