ENH: code modernization for decompose/reconstruct

- simplify procAddressing read/write

- avoid accessing points in faMeshReconstructor.
  Can rely on the patch meshPoints (labelList), which does not need
  access to a pointField

- report number of points on decomposed mesh.
  Can be useful additional information.
  Additional statistics for finite area decomposition

- provide bundled reconstructAllFields for various reconstructors

- remove reconstructPar checks for very old face addressing
  (from foam2.0 - ie, older than OpenFOAM itself)

- bundle all reading into fieldsDistributor tools,
  where it can be reused by various utilities as required.

- combine decomposition fields as respective fieldsCache
  which eliminates most of the clutter from decomposePar
  and similfies reuse in the future.

STYLE: remove old wordHashSet selection (deprecated in 2018)

BUG: incorrect face flip handling for faMeshReconstructor

- a latent bug which is not yet triggered since the faMesh faces are
  currently only definable on boundary faces (which never flip)

src/parallel/reconstruct/faReconstruct/faMeshReconstructor.C

@@ -77,7 +77,7 @@ void Foam::faMeshReconstructor::calcAddressing
     for (label& facei : faFaceProcAddr_)
     {
         // Use finiteVolume info, ignoring face flips
-        facei = mag(fvFaceProcAddr[facei] - 1);
+        facei = mag(fvFaceProcAddr[facei])-1;
     }
 
 
@@ -449,7 +449,7 @@ void Foam::faMeshReconstructor::initPatch() const
 
 void Foam::faMeshReconstructor::createMesh()
 {
-    const Time& runTime = procMesh_.mesh().time();
+    const Time& runTime = procMesh_.thisDb().time();
 
     // Time for non-parallel case (w/o functionObjects or libs)
     serialRunTime_ = Time::New(runTime.globalPath().toAbsolute());
@@ -654,7 +654,7 @@ void Foam::faMeshReconstructor::writeAddressing(const word& timeName) const
         "procAddressing",
         timeName,
         faMesh::meshSubDir,
-        procMesh_.mesh(),  // The polyMesh
+        procMesh_.thisDb(),
         IOobject::NO_READ,
         IOobject::NO_WRITE,
         false  // not registered
@@ -662,19 +662,19 @@ void Foam::faMeshReconstructor::writeAddressing(const word& timeName) const
 
     // boundaryProcAddressing
     ioAddr.rename("boundaryProcAddressing");
-    labelIOList(ioAddr, faBoundaryProcAddr_).write();
+    IOListRef<label>(ioAddr, faBoundaryProcAddr_).write();
 
     // faceProcAddressing
     ioAddr.rename("faceProcAddressing");
-    labelIOList(ioAddr, faFaceProcAddr_).write();
+    IOListRef<label>(ioAddr, faFaceProcAddr_).write();
 
     // pointProcAddressing
     ioAddr.rename("pointProcAddressing");
-    labelIOList(ioAddr, faPointProcAddr_).write();
+    IOListRef<label>(ioAddr, faPointProcAddr_).write();
 
     // edgeProcAddressing
     ioAddr.rename("edgeProcAddressing");
-    labelIOList(ioAddr, faEdgeProcAddr_).write();
+    IOListRef<label>(ioAddr, faEdgeProcAddr_).write();
 }
 
 
@@ -699,7 +699,7 @@ void Foam::faMeshReconstructor::writeMesh(const word& timeName) const
         IOobject io(fullMesh.boundary());
 
         io.rename("faceLabels");
-        labelIOList(io, singlePatchFaceLabels_).write();
+        IOListRef<label>(io, singlePatchFaceLabels_).write();
 
         fullMesh.boundary().write();