Ncrystal

* SPACEGROUP field is now optional in .ncmat files (but is always provided
in all official ones).
* The loadNCMAT function now accepts std::string for convenience.

* Change source for Quartz data file (results in small numerical changes only).
* Add new datafile for Sodalite.
* Updated year in copyright notice in all files.

* Fix small mistake preventing compilation of McStas component.

* Add three new materials, expanding coverage of data library: Uraninite,
Aragonite and SiLu2O5.
* Lower default dcutoff value for most .ncmat files to 0.1Aa, in response
to validation plots of Uraninite.
* Updated year in copyright notice in all files.
* Laz/Lau file loader now deals correctly with missing lattice_b/lattice_c
parameters, and performs sanity checks in all cases.
* Provide convenience functions/methods to Info objects, providing
d-spacing of a given hkl value.
* FillHKL use numerically stable summation when calculating structure factors.
* Add NCrystal version printout from the NCrystal_sample component in
McStas. Also sanity check the header file and library versions found.
* Add NCDebyeMSD utilities for getting mean squared atomic displacements
in the Debye model and use in .ncmat factory (to replace isotropic
Debye/Glauber model everywhere for consistency).
* For cosmetic reasons, avoid signed negative zero in atomic positions.
* Minor updates to .ncmat files (mostly cosmetic or rounding of numbers).

* Minor change in Geant4 interface to support Geant4 10.4 and later releases.

* Stop shipping hand-written .nxs files. Instead, attempt to auto-generate
.nxs files from all shipped .ncmat files, and where possible ship
those. This is done in order to ensure greater consistency and a lower
burden of maintenance moving forward. During this process a few issues
were found with Wyckoff positions in a few .nxs files, which should now
be fixed by the new procedure.
* Changed dcutoff for crystals with complex unit cells (like yttrium
oxide) from 0.4Aa to 0.25Aa when loading from .ncmat. For all other
.ncmat files in our data library, the value stays at 0.15Aa.
* Fix LCBragg error in case of the double degenerate case where both
neutron and lcaxis are parallel to (0,0,1).
* Faster fillHKL function, in particular for very small dcutoff values.
* The fillHKL function now supports the NCRYSTAL_FILLHKL_IGNOREFSQCUT
environment variable, which can be used to disable the fsquarecut entirely.
* Increased numerical stability in structure factor summation during
PCBragg initialisation.
* Phase out usage of non-standard constants like M_PI.
* Increase MC overlay safety factor slightly for LCBragg scatter generation.
* Improve colors and linestyles in ncrystal_inspectfile script.
* LCBraggRef models use numerically stable summation.