ENH: rewrite of foamToVTK to include parallel output (#926)

- Default format is now XML binary (base64) instead of legacy format.
  The old -xml option is redundant and ignored.
  The new -legacy option can be used to force legacy output instead.

- Polyhedral decomposition is now off by default (old -poly is ignored).
  The option -poly-decomp forces decomposition of polyhedrals into
  primitive shapes.

- reduced memory footprint by reading and converting fields
  successively.

- Creation of symlinks to processor files is no longer required or
  desired. The old -noLinks option is ignored.

- Ignore -useTimeName option. Always number according to timeIndex.

applications/utilities/postProcessing/dataConversion/foamToVTK/convertTopoSet.H

@@ -0,0 +1,88 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Description
+    Code chunk for converting face and point sets - included by foamToVTK.
+
+\*---------------------------------------------------------------------------*/
+
+// flag to top-level code to signal early stop.
+bool wroteTopoSet = false;
+
+// Write faceSet (as PolyData)
+if (faceSetName.size())
+{
+    // Load
+    faceSet set(mesh, faceSetName);
+
+    fileName outputName
+    (
+        outputDir/regionPrefix/"face-set"
+      / set.name()/set.name() + timeDesc
+    );
+
+    Info<< "    faceSet   : "
+        << outputName.relative(runTime.globalPath()) << nl;
+
+    vtk::writeFaceSet
+    (
+        mesh,
+        set,
+        writeOpts,
+        outputName,
+        Pstream::parRun()
+    );
+
+    wroteTopoSet = true;
+}
+
+
+// Write pointSet (as PolyData)
+if (pointSetName.size())
+{
+    // Load
+    pointSet set(mesh, pointSetName);
+
+    fileName outputName
+    (
+        outputDir/regionPrefix/"point-set"
+      / set.name()/set.name() + timeDesc
+    );
+
+    Info<< "    pointSet  : "
+        << outputName.relative(runTime.globalPath()) << nl;
+
+    vtk::writePointSet
+    (
+        mesh,
+        set,
+        writeOpts,
+        outputName,
+        Pstream::parRun()
+    );
+
+    wroteTopoSet = true;
+}
+
+
+// ************************************************************************* //