ENH: additional read guards for dimensionedType. input consistency (#762, #1148)

- provide a lookupOrDefault constructor form, since this is a fairly
  commonly used requirement and simplifies the calling sequence.

  Before

      dimensionedScalar rhoMax
      (
          dimensionedScalar::lookupOrDefault
          (
              "rhoMax",
              pimple.dict(),
              dimDensity,
              GREAT
          )
     );

  After

      dimensionedScalar rhoMax("rhoMax", dimDensity, GREAT, pimple.dict());

- read, readIfPresent methods with alternative lookup names.

- Mark the Istream related constructors with compile-time deprecated
  warnings.

BUG: read, readIfPresent methods not handling optional dimensions (#1148)

src/functionObjects/field/reference/referenceTemplates.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -36,16 +36,7 @@ bool Foam::functionObjects::reference::calcType()
     {
         const VolFieldType& vf = *vfPtr;
 
-        dimensioned<Type> offset
-        (
-            dimensioned<Type>::lookupOrDefault
-            (
-                "offset",
-                localDict_,
-                vf.dimensions(),
-                Zero
-            )
-        );
+        dimensioned<Type> offset("offset", vf.dimensions(), Zero, localDict_);
 
         dimensioned<Type> cellValue("value", vf.dimensions(), Zero);