ENH: improve robustness of scalarRanges from string (fixes #673)

- now avoid Istream and token mechanism in favour of a simpler string
  parser. This makes the code clearer, smaller, robuster.

- provide convenience ge/gt/le/lt static constructors for scalarRange
  for using bounds directly with specifying via a string parameter.

- scalarRange, scalarRanges now follow the unary predicate pattern
  (using an operator() for testing). This allows their reuse in
  other contexts. Eg, for filtering operations:

      myHash.filterValues(scalarRange::ge(100));

- remove unused scalarRanges methods that were specific to handling
  lists of time values. These were superseded by timeSelector methods
  several versions ago.

applications/test/scalarRanges/Make/files

@@ -0,0 +1,3 @@
+Test-scalarRanges.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-scalarRanges

applications/test/scalarRanges/Test-scalarRanges.C

@@ -0,0 +1,112 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Description
+    Test scalar ranges
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "scalarRanges.H"
+
+using namespace Foam;
+
+
+template<class HTable>
+Ostream& printHash(const HTable& h)
+{
+    const auto keys = h.sortedToc();
+
+    Info<<"keys: " << keys.size() << "(";
+    for (const auto& k : keys)
+    {
+        Info<<" " << k;
+    }
+    Info<< " )" << nl;
+
+    Info<<"vals: " << keys.size() << "(";
+    for (const auto& k : keys)
+    {
+        Info<<" " << h[k];
+    }
+    Info<< " )" << nl;
+
+    return Info;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+//  Main program:
+
+int main(int argc, char *argv[])
+{
+    argList::noParallel();
+    argList::noFunctionObjects();
+    argList::addArgument("range,range range,range");
+    argList::addNote
+    (
+        "Test parsing of comma-separated ranges\n\n"
+        "Eg, ':10,20,40:70,1000:'"
+    );
+
+    argList args(argc, argv, false, true);
+
+    HashTable<scalar> testHash;
+    for (label i = 0; i < 26; ++i)
+    {
+        word key("X");
+        key[0] = 'a' + i;
+        testHash.insert(key, i);
+
+        key[0] = 'A' + i;
+        testHash.insert(key, 100 + i);
+    }
+
+    printHash(testHash)
+        << nl;
+
+    for (int argi = 1; argi < argc; ++argi)
+    {
+        Info<<"tokenize " << args[argi] << nl;
+
+        scalarRanges ranges(args[argi]);
+        Info<<"=> " << ranges << endl;
+
+        HashTable<scalar> subHash(testHash);
+        subHash.filterValues(ranges);
+
+        Info<<"filtered:" << nl;
+
+        printHash(subHash)
+            << nl;
+
+        subHash.filterValues(scalarRange::le(8));
+        Info<<"filtered <= 8:" << nl;
+
+        printHash(subHash)
+            << nl;
+    }
+
+    return 0;
+}
+
+// ************************************************************************* //