Rationalised and standardised cell, face and point set selection controls

The keyword 'select' is now used to specify the cell, face or point set
selection method consistently across all classes requiring this functionality.

'select' replaces the inconsistently named 'regionType' and 'selectionMode'
keywords used previously but backwards-compatibility is provided for user
convenience.  All configuration files and tutorials have been updated.

Examples of 'select' from the tutorial cases:

functionObjects:

    cellZoneAverage
    {
        type            volFieldValue;
        libs            ("libfieldFunctionObjects.so");

        writeControl    writeTime;
        writeInterval   1;

        fields          (p);
        select          cellZone;
        cellZone        injection;

        operation       volAverage;
        writeFields     false;
    }

    #includeFunc populationBalanceSizeDistribution
    (
        name=numberDensity,
        populationBalance=aggregates,
        select=cellZone,
        cellZone=outlet,
        functionType=numberDensity,
        coordinateType=projectedAreaDiameter,
        allCoordinates=yes,
        normalise=yes,
        logTransform=yes
    )

fvModel:

    cylinderHeat
    {
        type            heatSource;

        select          all;

        q               5e7;
    }

fvConstraint:

    momentumForce
    {
        type            meanVelocityForce;

        select          all;

        Ubar            (0.1335 0 0);
    }

tutorials/modules/incompressibleFluid/channel395/system/fvConstraints

@@ -18,7 +18,7 @@ momentumForce
 {
     type            meanVelocityForce;
 
-    selectionMode   all;
+    select          all;
 
     Ubar            (0.1335 0 0);
 }

tutorials/modules/incompressibleFluid/ductSecondaryFlow/system/fvConstraints

@@ -18,7 +18,7 @@ momentumSource
 {
     type            meanVelocityForce;
 
-    selectionMode   all;
+    select          all;
 
     Ubar            (0 0 1.95);
 }

tutorials/modules/incompressibleFluid/mixerSRF/constant/MRFProperties

@@ -16,7 +16,7 @@ FoamFile
 
 SRF
 {
-    selectionMode   all;
+    select          all;
 
     origin      (0 0 0);
     axis        (0 0 1);

tutorials/modules/incompressibleFluid/planarPoiseuille/constant/fvModels

@@ -18,7 +18,7 @@ momentumSource
 {
     type            semiImplicitSource;
 
-    selectionMode   all;
+    select          all;
 
     volumeMode      specific;
 

tutorials/modules/incompressibleFluid/rotor2DRotating/constant/dynamicMeshDict

@@ -22,7 +22,7 @@ mover
 
     motionSolver    solidBody;
 
-    selectionMode   all;
+    select          all;
 
     solidBodyMotionFunction  rotatingMotion;
 

tutorials/modules/incompressibleFluid/rotor2DSRF/constant/MRFProperties

@@ -16,7 +16,7 @@ FoamFile
 
 SRF
 {
-    selectionMode   all;
+    select          all;
 
     origin    (0 0 0);
     axis      (0 0 1);