ENH: Function1 and PatchFunction1 improvements (#1917)

- easier support for non-mandatory functions.

  In some boundary conditions it can be desirable to support
  additional functions, but not necessarily require them. Make this
  easier to support with a Function1, PatchFunction1 NewIfPresent()
  selector.

- support for compatibility lookups

- harmonize branching logic and error handling between Function1 and
  PatchFunction1.

ENH: refactor a base class for Function1, PatchFunction1

- includes base characteristics, patch or scalar information

ENH: additional creation macros

- makeConcreteFunction1, makeConcretePatchFunction1Type for adding a
  non-templated function into the correct templated selection table.
  makeScalarPatchFunction1 for similarity with makeScalarFunction1

src/OpenFOAM/primitives/functions/Function1/Scale/Scale.C

@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2017 OpenFOAM Foundation
+    Copyright (C) 2020 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -61,6 +62,14 @@ Foam::Function1Types::Scale<Type>::Scale(const Scale<Type>& rhs)
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class Type>
+void Foam::Function1Types::Scale<Type>::writeEntries(Ostream& os) const
+{
+    scale_->writeData(os);
+    value_->writeData(os);
+}
+
+
 template<class Type>
 void Foam::Function1Types::Scale<Type>::writeData(Ostream& os) const
 {
@@ -68,10 +77,7 @@ void Foam::Function1Types::Scale<Type>::writeData(Ostream& os) const
     os  << token::END_STATEMENT << nl;
 
     os.beginBlock(word(this->name() + "Coeffs"));
-
-    scale_->writeData(os);
-    value_->writeData(os);
-
+    writeEntries(os);
     os.endBlock();
 }