Enabled postProcess on film region for reactingParcelFoam

This change enables function objects to be executed on the film region using the postProcess utility/option.

Cross-ref EP 1105

@Prashant

applications/solvers/lagrangian/reactingParcelFoam/createMeshesPostProcess.H

+#include "createMesh.H"
+
+IOdictionary filmDict
+(
+    IOobject
+    (
+        "surfaceFilmProperties",
+        runTime.constant(),
+        runTime,
+        IOobject::MUST_READ,
+        IOobject::NO_WRITE,
+        false
+    )
+);
+
+const word filmRegionName = filmDict.get<word>("region");
+
+fvMesh filmMesh
+(
+    IOobject
+    (
+        filmRegionName,
+        runTime.timeName(),
+        runTime,
+        IOobject::MUST_READ
+    )
+);
+