- reverse mapping for the original point ids. This can be useful
  when searching a subset of points, but needing to store access to
  the original point index.

- move constructor.

- Allow use/not-use subset as an optional constructor argument for
  more convenient caller logic.

- add PDRblockMeshDict example for cavity

- don't need extra nullptr check for some cases. Less clutter.

- changed for 1906 to have a regIOobject always cleanup its
  objectRegistry entry. No need to explicitly 'release' ownership
  for this to now happen.

- doxygen formatting for MeshObject

Caveat: The -Wdeprecated-copy produces many, many compiler warnings

TODO: need to revisit

- if desired to create a tar-file without a _patch value in its name.

- add a '-SPDP' option

- remove the '-archOption' for forcing a '-m32' build on 64-bit
  architecture, which is now considered too obscure.
  Must edit files manually if this option is really required.

Digital-Filter Based Synthetic Turbulence Generation Method for LES/DES Inflow

See merge request Development/OpenFOAM-plus!235