Spherical-geometry

=======================

- Updated the built-in ``qd`` library to version 2.3.24. [258]

=======================

- Add documentation to ``polygon.py`` for the ``SphericalPolygon``
method ``multi_union`` has exponential time behavior and cannot
be used for a large number of polynomials [229]

- Added code to ``SphericalPolygon.multi_union()`` to pre-process
polygon list and remove nearly identical polygons to avoid a bug in the
``graph`` code that could cause a crash when some of the input polygons are
nearly identical. This workaround can be undone in the future once
https://github.com/spacetelescope/spherical_geometry/issues/232
is resolved. [233]

- Removed unused ``spherical_geometry.utils`` module. [239]

- Minimum supported version for Python is now 3.9. [239]

- Minimum supported version for NumPy is now 1.20. [239]

- Wheels for several common architectures are now available on PyPI. [243]

- Replaced private ``numpy.core._umath_tests.inner1d()`` with an alternative
implementation. [253]

- Fixed a bug in the ``math_util.angles()`` function that would result in crash
when one of the input vectors is a null vector. [254]

- Enhanced the code in the ``SphericalPolygon.convex_hull()`` to ignore points
that lead to null vectors in computations. [254]

- Fixed a bug in quad-precision functions ``normalize`` and
``intersection`` functions affecting numerous other functions. [256]

========================

- Pin astropy min version to 5.0.4. [218]

- Set Python min version to 3.8. [219]

- Fix problem reported where angle of 180 degrees results in an
error with the C version of the code. [223]

- Use a different algorithm for square root in the ``qd`` library that
seems to be less prone to accuracy loss. This helps the bug in the
``math_util.c`` due to which ``angle()`` returns a NaN for
coplanar vectors where the angle between the surface points should be
180 degrees and enhances the solution from 223. Also, use ``qd`` epsilon
instead of arbitrary value for rounding error check. [224]

========================

- Fixed segmentation fault occuring in the ``math_util`` module when
``spherical_geometry`` is used with ``numpy`` version ``1.22`` due to
incorrect ``ntypes`` value being used when defining generalized
universal functions. [216]

=========================

Maintenance release.

====================

- Added a new exception class ``MalformedPolygonError`` which replaces
``ValueError`` which replaced ``AssertionError`` in the
``Graph._sanity_check()`` method. Also replaced ``ValueError`` with
``RuntimeError`` in ``Graph.Edge.follow()`` method. Added error
messages to some other exceptions. [207]

- Updated CI/CD to use github actions, instead of Travis CI.

- To comply with ``bandit`` all ``assert`` statements were changed to standard
``if`` checks and raising the appropriate errors.