------------------
- Prevent same WCS from being updated from astrometry database headerlet. [111]
- Revise how headerlets are applied as primary WCS [122]
- Add comments to WCS keywords for ``IDC*``, ``OCX``, ``OCY``, and alternate
WCS. [127]
- Primary WCS keywords no longer contain trailing spaces which, in the past,
lead to duplicate keywords in image headers. [131]
- AltWCS: Non-standard WCS keywords defined by, e.g., ``TweakReg`` are now
archived, read, and restored together with standard WCS keywords. [135]
- WCS keywords that are not specific to an alternate WCS (such as ``MJDREF``)
are no longer archived. [141]
- Fix a bug in ``_restore()`` due to which ``TDDALPHA`` and ``TDDBETA`` were
not reset to ``0.0`` when restoring wrom the ``'OPUS'`` WCS with key ``'O'``. [141]
- Increased reliability of detecting alternate WCS in image headers. [141]
- Abbreviated comments for ``D2IM``, ``CPDIS`` lookup table distortions. [142]
- Add comments to ``WCSNAMEa`` header keywords. [143]
- Do not archive primary WCS when applying headerlet as primary when existing
primary WCS was created from the same headerlet that is being applied, based
on the value of ``'HDRNAME'`` keyword. [147]
- Added ``archive_wcs()`` function with more advanced control over how to
archive primary WCS and with more capabilities, such as auto-renaming. [153]
- Remove HST-specific WCS keywords from SCI extensions that, following HST
convention, are supposed to be present in primary header only. [159]
- Do not archive primary WCS when applying headerlet as primary if distortion
model changes. [161]