OpenFOAM field reading: Automated the handling of <field>.orig files

Now if a <field> file does not exist first the compressed <field>.gz file is
searched for and if that also does not exist the <field>.orig file is searched
for.

This simplifies case setup and run scripts as now setField for example can read
the <field>.orig file directly and generate the <field> file from it which is
then read by the solver.  Additionally the cleanCase function used by
foamCleanCase and the Allclean scripts automatically removed <field> files if
there is a corresponding <field>.orig file.  So now there is no need for the
Allrun scripts to copy <field>.orig files into <field> or for the Allclean
scripts to explicitly remove them.

tutorials/multiphase/reactingMultiphaseEulerFoam/laminar/bubbleColumnFixedPolydisperse/0/alpha.airI

@@ -1,47 +0,0 @@
-/*--------------------------------*- C++ -*----------------------------------*\
-| =========                 |                                                 |
-| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
-|  \\    /   O peration     | Version:  dev                                   |
-|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
-|    \\/     M anipulation  |                                                 |
-\*---------------------------------------------------------------------------*/
-FoamFile
-{
-    version     2.0;
-    format      ascii;
-    class       volScalarField;
-    location    "0";
-    object      alpha.airI;
-}
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-dimensions      [0 0 0 0 0 0 0];
-
-internalField   uniform 0;
-
-boundaryField
-{
-    inlet
-    {
-        type            fixedValue;
-        value           uniform 0.25;
-    }
-    outlet
-    {
-        type            inletOutlet;
-        phi             phi.airI;
-        inletValue      uniform 0;
-        value           uniform 0;
-    }
-    walls
-    {
-        type            zeroGradient;
-    }
-    defaultFaces
-    {
-        type            empty;
-    }
-}
-
-
-// ************************************************************************* //

tutorials/multiphase/reactingMultiphaseEulerFoam/laminar/bubbleColumnPolydisperse/0/alpha.airI

@@ -1,47 +0,0 @@
-/*--------------------------------*- C++ -*----------------------------------*\
-| =========                 |                                                 |
-| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
-|  \\    /   O peration     | Version:  dev                                   |
-|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
-|    \\/     M anipulation  |                                                 |
-\*---------------------------------------------------------------------------*/
-FoamFile
-{
-    version     2.0;
-    format      ascii;
-    class       volScalarField;
-    location    "0";
-    object      alpha.airI;
-}
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-dimensions      [0 0 0 0 0 0 0];
-
-internalField   uniform 0;
-
-boundaryField
-{
-    inlet
-    {
-        type            fixedValue;
-        value           uniform 0.25;
-    }
-    outlet
-    {
-        type            inletOutlet;
-        phi             phi.airI;
-        inletValue      uniform 0;
-        value           uniform 0;
-    }
-    walls
-    {
-        type            zeroGradient;
-    }
-    defaultFaces
-    {
-        type            empty;
-    }
-}
-
-
-// ************************************************************************* //