for correct run time reading.
Setting up twoSimpleRotors tutorial for smooth pressure
fluctuations

Previously had 3 possibilities for handling exposed internal faces

  1. use default "oldInternalFaces"
  2. specify -patch, to use the specified (existing) patch
  3. specify -patches, to use the geometrically closest patches

Now relaxed the restriction on -patch to allow specification of a new
(not yet existing) patch name. This improves flexibility, but won't
catch typing mistakes.

Harmonize behaviour of -patches and -patch. When -patches is used to
specify a single, non-regex patch name, it now behaves identically to
-patch. Since the getList handling for options already allows special
treatment for single parameter lists, the following will work
identically:

      subsetMesh -patch  patch0
      subsetMesh -patches patch0
      subsetMesh -patches '( patch0 )'

In the future it might be reasonable to fully combine the behaviour of
'-patch' and '-patches' and treat them as aliases for each other.

ENH: support subsetMesh on a cellZone.

- when the '-zone' option is specified, the command argument is treated
  as the name (or names) of cellZones to be selected instead of as the
  name of the cellSet.

  The command argument can be a single word, regex, or list of
  word/regex.
  Eg,

      subsetMesh -zone -patch mypatch  mixer
      subsetMesh -zone -patch mypatch  '(mixer "moving.*" )'

STYLE: simplify set handling and other code cleanup in subsetMesh

- handling of cloud coordinates/positions between mapFields, mapFieldsPar

- safeguard against any change in the default in cylindricalCS

    Using: OpenFOAM-plus (see www.OpenFOAM.com)
    Build: plus-7ab57cc5 (OPENFOAM=1807)
    Arch:  LSB;label=32;scalar=64

- This can be useful for development versions, or when the version
  at build time uses some other naming scheme (#1010)

- superseded by the vtkCloud function object, which provides
  significantly more functionality and more versatile output
  (using the vtp format).

- an alternative to distanceSurface (with distance zero) that uses
  a cell cutting approach instead of an iso-surface.

- 'signed' input parameter only mandatory for distance > 0.
  A distance <= 0 is always signed and the input parameter is ignored.

- Use normal distance when distance == 0. This has no effect when
  the surface has no open edges, but improves on rounding issues
  around the zero crossing when the surface has open edges.

  This may still need future revisiting.

- avoid duplicate code by relocating cellZone selection and bounding box
  sub-selection into cuttingPlane and cuttingSurfaceBaseSelection.
  Allows reuse by inherited classes (sampledPlane, surfMeshSamplePlane).

- takes two general actions:
  1. orient edge in canonical direction (positive gradient) and detect
     any edge intersection.
  2. edge intersection alpha (0-1)

- refactor into a cuttingSurfaceBase intermediate class with the
  actions as templated parameters rather than function pointers. This
  allows the use of lambda functions with captures from the caller.

- The test condition

      [ -n "$cur" -a ... ]

  fails if $cur starts with '-le', which bash interprets as a further
  test op. Splitting the test condition solves the problem:

      [ -n "$cur" ] && [ ... ]

- Since the local edges are oriented according to the gradient,
  they can also be used to determine the correct face orientation.

This generalizes the algorithm for future reuse.

- simple check for unique and non-negative point labels

- for installations with central (non-ThirdParty) location for KAHIP
  (eg, spack, EasyBuild)

- replaces previous pointer conversion

- uses int, without enclosing brackets.