ENH: improve consistency of ListOps and stringListOps

- subsetList, inplaceSubsetList with optional inverted logic.

- use moveable elements where possible.

- allow optional starting offset for the identity global function.
  Eg,  'identity(10, start)' vs 'identity(10) + start'

src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C

@@ -619,8 +619,11 @@ void Foam::meshRefinement::checkData()
         localPointRegion::findDuplicateFaces
         (
             mesh_,
-            identity(mesh_.nFaces()-mesh_.nInternalFaces())
-          + mesh_.nInternalFaces()
+            identity
+            (
+                mesh_.nFaces() - mesh_.nInternalFaces(),
+                mesh_.nInternalFaces()
+            )
         )
     );