CONT: Addition of compressibleIsoInterFOam and PLIC

1) Implementation of the compressibleIsoInterFOam solver
   2) Implementation of a new PLIC interpolation scheme.
   3) New tutorials associated with the solvers

This implementation was carried out by Henning Scheufler (DLR) and Johan
Roenby (DHI), following :

\verbatim

Henning Scheufler, Johan Roenby,
Accurate and efficient surface reconstruction from volume fraction data
on general meshes, Journal of Computational Physics, 2019, doi
10.1016/j.jcp.2019.01.009

\endverbatim

The integration of the code was carried out by Andy Heather and Sergio
Ferraris from OpenCFD Ltd.

applications/test/multiDimPolyFitter/Make/files

@@ -0,0 +1,3 @@
+Test-multiDimPolyFitter.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-multiDimPolyFitter

applications/test/multiDimPolyFitter/Make/options

@@ -0,0 +1,9 @@
+EXE_INC = \
+    -I$(LIB_SRC)/finiteVolume/lnInclude \
+    -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/sampling/lnInclude
+
+EXE_LIBS = \
+    -lfiniteVolume \
+    -lmeshTools \
+    -lsampling

applications/test/multiDimPolyFitter/Test-multiDimPolyFitter.C

@@ -0,0 +1,113 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2020 DLR
+-------------------------------------------------------------------------------
+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/>.
+
+Application
+    Test-multiDimPolyFitter
+
+Description
+
+\*---------------------------------------------------------------------------*/
+
+#include "fvCFD.H"
+#include "multiDimPolyFitter.H"
+#include "labelVector.H"
+#include "Field.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+int main(int argc, char *argv[])
+{
+    labelVector test(1,-1,-1);
+
+    autoPtr<multiDimPolyFunctions> polyFunc
+        = multiDimPolyFunctions::New("polyDegree1", test);
+
+    vector vec(1,2,3);
+
+    Info<< "polyFunc" << nl
+        << "    nTerms " << polyFunc->nTerms() << nl
+        << "    coeffs " << polyFunc->coeffs() << nl
+        << "    termValues " << polyFunc->termValues(vec) << nl;
+
+    multiDimPolyFitter<scalar> polyFitter("polyDegree1",test);
+
+    List<vector> pos
+    ({
+        {0,0,0},
+        {1,0,0},
+        {-1,0,0}
+    });
+
+    List<scalar> values
+    ({
+        1, 2, 0
+    });
+
+    Info<< "pos " << pos << nl
+        << "values " << values  << nl;
+
+    scalarField fitData = polyFitter.fitData(pos, values);
+
+    Info<< "fitData " << fitData  << nl;
+
+    autoPtr<multiDimPolyFunctions> polyFuncDeg2
+        = multiDimPolyFunctions::New("polyDegree2", labelVector(1,1,-1));
+
+    //vector vec(1,2,3);
+
+    Info<< "polyFunc" << nl
+        << "    nTerms" << polyFuncDeg2->nTerms()  << nl
+        // << "    coeffs " << polyFunc->coeffs()  << nl
+        << "    termValues " << polyFuncDeg2->termValues(vector(1,1,0)) << nl;
+
+    List<vector> pos2
+    ({
+        {0,0,0},
+        {1,0,0},
+        {-1,0,0},
+        {0,1,0},
+        {0,-1,0},
+        {1,1,0}
+    });
+
+    List<scalar> values2
+    ({
+        0, 1, 1, 1, 1, 2
+    });
+
+    multiDimPolyFitter<scalar> polyFitter2
+    {
+        "polyDegree2", labelVector(1,1,-1)
+    };
+
+    scalarField fitData2 = polyFitter2.fitData(pos2, values2);
+
+    Info<< "fitData " << fitData2  << nl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //