functionObjects::specieFlux: New functions to calculate specie fluxes

These functions calculate the specie-flux and write it as a
surfaceScalarField called 'specie<Type>Flux(<specieName>)'. There are
three such functions; specieAdvectiveFlux and specieDiffusiveFlux return
the advective and diffusive parts of the flux, respectively, and
specieFlux returns the total combined flux.

Example of function object specification:

    specieFlux
    {
        type    specieFlux; // specieAdvectiveFlux, specieDiffusiveFlux
        libs    ("libfieldFunctionObjects.so");
        field   NH3;
    }

Or, using the standard configuration:

    #includeFunc specieFlux(NH3)

tutorials/multicomponentFluid/membrane/Allclean

@@ -0,0 +1,9 @@
+#!/bin/sh
+cd ${0%/*} || exit 1    # Run from this directory
+
+# Source tutorial clean functions
+. $WM_PROJECT_DIR/bin/tools/CleanFunctions
+
+cleanCase && rm -rf 0/specieFlux* 0/uniform
+
+#------------------------------------------------------------------------------

tutorials/multicomponentFluid/membrane/system/functions

@@ -0,0 +1,41 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    format      ascii;
+    class       dictionary;
+    location    "system";
+    object      functions;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#includeFunc specieFlux(O2, schemesField=Yi_h, executeControl=timeStep)
+
+#includeFunc specieFlux(CH4, schemesField=Yi_h, executeControl=timeStep)
+
+#includeFunc specieFlux(N2, schemesField=Yi_h, executeControl=timeStep)
+
+#includeFunc patchIntegrate
+(
+    name=membraneSleeveSpecieFluxes,
+    patch=membraneSleeve,
+    specieFlux(O2),
+    specieFlux(CH4),
+    specieFlux(N2)
+)
+
+#includeFunc patchIntegrate
+(
+    name=membranePipeSpecieFluxes,
+    patch=membranePipe,
+    specieFlux(O2),
+    specieFlux(CH4),
+    specieFlux(N2)
+)
+
+// ************************************************************************* //