Ihm

=================
- Strings that start with STAR reserved words such as ``stop_`` are now
quoted to help some readers such as the GEMMI library
(ihmwg/python-modelcif25).
- If an input file defines a chemical descriptor with an empty name
but also defines ``linker_type``, use that to fill in the name (91).
- :class:`ihm.ChemComp` now allows for chemical components to be defined
in a chemical component dictionary (CCD) outside of the wwPDB CCD. This
is not used in python-ihm itself but can be used in python-modelcif.
- Bugfix: if a read mmCIF file defines a complete assembly, do not overwrite
its name and description on output (92).
- Bugfix: only allow clustering methods/features that are supported by
the underlying IHM dictionary for :class:`ihm.model.Ensemble` (94).
- Bugfix: categories such as ``_struct`` that are not typically looped
now support multi-line strings (ihmwg/python-modelcif27).

=================
- Improve reading of mmCIF files with incomplete data (86, 87) or with
categories in an unexpected order (85).
- Bugfix: fix sanity check for multiple atoms with the same atom_id and
seq_id to handle bulk water (where such duplicates are OK) (88).

=================
- :class:`ihm.protocol.Step` now takes an ``ensemble`` flag, to indicate
whether the modeling involved an ensemble, and which defaults to True if
the system contains at least one :class:`ihm.model.Ensemble` (83).
- When reading an incomplete mmCIF file, such as that generated by some
versions of PyMOL, python-ihm will now fill in missing entity-related
information by guessing the sequence from the atom_site table (67).
- Bugfix: :class:`ihm.flr.RefMeasurementGroup` objects are now read
from mmCIF files correctly.

=================
- The :class:`ihm.dumper.IgnoreVariant` class can now be used to exclude
selected categories from the mmCIF/BinaryCIF output.
- The _pdbx_nonpoly_scheme CIF table should now fully comply with the
PDBx dictionary.
- Atoms are now checked at file-output time to ensure that a given model
chain does not contain multiple atoms with the same atom_id and
seq_id (81).

=================
- Add support for a long description of the system (like an abstract)
using struct.pdbx_model_details (80).
- Bugfix: correctly read mmCIF files with missing entity.type.

=================
- Output mmCIF files containing non-polymers should now validate against
the PDBx dictionary (76).
- Bugfix: non-polymers that are erroneously marked as polymers in
the input mmCIF can now be read in without causing a Python
exception (78).
- Bugfix: strings starting with an underscore (e.g. chain names) are now
quoted in mmCIF output to conform to the CIF syntax (75).