- changed the sectorCoeffs keyword to 'point' from 'axisPt'
  for more similarity with other dictionaries.
  Continue to accept 'axisPt' for compatibility.

- allows use in surfMesh library, which does not depend on meshTools

Feature run time control triggers

See merge request OpenFOAM-plus!228

- now free anything owned by the registry when doing a clear.

- the myriad of other ways to remove items (and potentially leaking)
  have not yet been addressed:
  * set, erase, retain, filterKeys, filterValues, filterEntries

- checkIn() was incorrectly conditional on the register state of the
  source object.

Partial patch from .org commit 6dc48b62d948

- Uses the user-specified value for the HTC calculation

  {
      type  externalCoupledTemperature;

      outputTemperture    fluid;  // or wall;
      htcRefTemperature   user;   // or cell (default)

      Tref    293.15;
  }

- was for parallel compilation across multiple hosts, but less useful
  with modern CPUs with higher number of cores and/or hyperthreading.

  Fragile use and dependent on a 'lockfile' utility that is not often
  installed.

- previously stated that the patch level would be 0, but this would
  necessitate many revert commits after merging in the master branch.
  It is better to leave the meaning open.

- since foamDictionary doesn't use system/controlDict it will use the
  standard default precision. The '-precision' option allows adjusting
  that value.

- support for optional 'enabled' keyword to selectively disable a
  single sampled surface.

ENH: add sampledSurface::withSurfaceFields() method

- can be used to distinguish which samplers support surface fields.
  Currently this is only sampledPatch

- moves any nullptr to the end of the list where they can be
  eliminated in a second step with resize()