ENH: processorField: added etc/caseDicts file. Fixes #807.

etc/caseDicts/postProcessing/fields/processorField

+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Web:      www.OpenFOAM.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Writes a volScalarField with processor number. Useful for postprocessing.
+
+\*---------------------------------------------------------------------------*/
+
+type            processorField;
+libs            ("libfieldFunctionObjects.so");
+
+executeControl  writeTime;
+writeControl    writeTime;
+
+// ************************************************************************* //