- this allows the sys-admin to provide base values independent of any
  WM_PROJECT_SITE value.

- support names like openfoam-<VERSION> (eg, what spack uses).
- robustness improvements

- this corresponds to what various module or build systems provide.
  ThirdParty builds are unaffected since they install into FOAM_EXT_LIBBIN

of the specified type

e.g. postProcess -time 0.001 -func dsmcFields

Resolves bug-report https://bugs.openfoam.org/view.php?id=2499

Resolves patch request https://bugs.openfoam.org/view.php?id=2490

Set default value of C3 to 0
Set C3 to -0.33 in the engineFoam/kivaTest tutorial.

Resolves bug-report https://bugs.openfoam.org/view.php?id=2496

Resolves bug-report https://bugs.openfoam.org/view.php?id=2492

Resolves bug-report https://bugs.openfoam.org/view.php?id=2491

Formally this is equivalent to the previous formulation but more convenient to
use given that for compressible flow the mass flux rather than the volume flux
is available.

sixDoFRigidBodyDisplacementPointPatchVectorField, uncoupledSixDoFRigidBodyDisplacementPointPatchVectorField: removed

These legacy boundary conditions are no longer needed and have been superseded
by the more flexible sixDoFRigidBodyMotion and rigidBodyMotion solvers.  See tutorials:

incompressible/pimpleDyMFoam/wingMotion/wingMotion2D_pimpleDyMFoam
multiphase/interDyMFoam/RAS/DTCHull
multiphase/interDyMFoam/RAS/floatingObject

Resolves bug-report https://bugs.openfoam.org/view.php?id=2487

Resolves bug-report https://bugs.openfoam.org/view.php?id=2459

Resolves bug-report https://bugs.openfoam.org/view.php?id=2489

Using

decomposePar -copyZero

The mesh is decomposed as usual but the '0' directory is recursively copied to
the 'processor.*' directories rather than decomposing the fields.  This is a
convenient option to handle cases where the initial field files are generic and
can be used for serial or parallel running.  See for example the
incompressible/simpleFoam/motorBike tutorial case.

Patch contributed by Mattijs Janssens

Fewer limiter iterations are now required to obtain sufficient boundedness and
restart is more consistent.

- this makes it possible to perform additional operations
  on surface values that have been previously sampled.

- support vectorField for weighting operations.

- reduce overhead by avoiding creation of weight fields, Sf fields
  and combined surface geometries unless they are actually required.

- extend some similar concepts and operations to volFieldValue

PBiCGStab has proved more reliable than PCG for solving the pressure equation in
compressible systems.

Resolves bug-report https://bugs.openfoam.org/view.php?id=2475

Both stardard SIMPLE and the SIMPLEC (using the 'consistent' option in
fvSolution) are now supported for both subsonic and transonic flow of all
fluid types.

rhoPimpleFoam now instantiates the lower-level fluidThermo which instantiates
either a psiThermo or rhoThermo according to the 'type' specification in
thermophysicalProperties, see also commit a1c8cde3