STYLE: relegate special purpose readList<T> function to points of use

- the readList<T>(Istream&) function was introduced to handle command
  -options with either a single or a list value, but was also used for
  the #remove dictionary directive. However, the parsing was fragile
  if the list did not start with a '('.
  Now handle command-line arg/option list directly (via ITstream)
  and #remove with special-purpose reading of a string or word list.

  This removes ambiguity and reduces potential future problems.

STYLE: use ITstream instead of IStringStream for command-line lookups

- parses directly to a tokenList without a string copy.

src/OpenFOAM/db/dictionary/functionEntries/functionEntry/functionEntry.H

@@ -67,9 +67,6 @@ class functionEntry
 {
     // Private Member Functions
 
-        //- Read line as string token
-        static token readLine(const word& key, Istream& is);
-
         //- Disallow default bitwise copy construct
         functionEntry(const functionEntry&) = delete;
 
@@ -77,6 +74,16 @@ class functionEntry
         void operator=(const functionEntry&) = delete;
 
 
+protected:
+
+        //- Read line and return as a string token
+        static token readLine(const word& key, Istream& is);
+
+        //- Read a List of strings values, treating a single entry like a
+        //- list of size 1.
+        template<class StringType>
+        static List<StringType> readStringList(Istream& is);
+
 public:
 
     // Constructors
@@ -142,6 +149,12 @@ public:
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
+#ifdef NoRepository
+    #include "functionEntryTemplates.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
 #endif
 
 // ************************************************************************* //