ENH: cleanup and rationalize memory-backed streams

- more consistent naming:
  * Versions that hold and manage their own memory:
      IListStream, OListStream

  * Versions that reference a fixed size external memory:
      UIListStream, UOListStream

- use List storage instead of DynamicList within OListStream.
  Avoids duplicate bookkeeping, more direct handling of resizing.

applications/test/IListStream/Make/files

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

applications/test/IListStream/Make/options

@@ -0,0 +1,2 @@
+/* EXE_INC = */
+/* EXE_LIBS = */

applications/test/IListStream/Test-IListStream.C

@@ -0,0 +1,151 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 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
+
+\*---------------------------------------------------------------------------*/
+
+#include "ListStream.H"
+#include "UListStream.H"
+#include "wordList.H"
+#include "IOstreams.H"
+#include "argList.H"
+
+using namespace Foam;
+
+Ostream& toString(Ostream& os, const UList<char>& list)
+{
+    os << '"';
+    for (const char c : list)
+    {
+        os << c;
+    }
+    os << '"';
+
+    return os;
+}
+
+
+template<class BufType>
+void printInfo(const BufType& buf)
+{
+    Info<< nl << "=========================" << endl;
+    buf.print(Info);
+    toString(Info, buf.list());
+    Info<< nl << "=========================" << endl;
+}
+
+
+void printTokens(Istream& is)
+{
+    label count = 0;
+    token t;
+    while (is.good())
+    {
+        is >> t;
+        if (t.good())
+        {
+            ++count;
+            Info<<"token: " << t << endl;
+        }
+    }
+
+    Info<< count << " tokens" << endl;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    // Buffer storage
+    DynamicList<char> storage(16);
+
+    OListStream obuf(std::move(storage));
+    obuf << 1002 << " " << "abcd" << " " << "def" << " " << 3.14159 << ";\n";
+
+    // Move contents to output buffer
+    printInfo(obuf);
+
+    Info<<nl << "as string: ";
+    toString(Info, obuf.list()) << endl;
+
+    Info<< "transfer contents to a List" << endl;
+
+    IListStream ibuf(obuf.xfer());
+
+    Info<< nl;
+    Info<< nl << "input string:";
+    printInfo(ibuf);
+
+    Info<< nl << "orig output:";
+    printInfo(obuf);
+
+    printTokens(ibuf);
+
+    Info<<nl << "after:";
+    printInfo(ibuf);
+
+    // This should also work
+    ibuf.list() = 'X';
+
+    Info<<nl << "overwritten with const value:";
+    printInfo(ibuf);
+
+    // Can also change content like this:
+    {
+        const int n = min(26, ibuf.size());
+
+        for (int i=0; i<n; ++i)
+        {
+            ibuf.list()[i] = 'A' + i;
+        }
+    }
+
+    Info<<nl << "directly written:";
+    printInfo(ibuf);
+
+    // But cannot easily swap in/out an entirely new list storage:
+    //
+    // List<char> newvalues(52);
+    // {
+    //     for (int i=0; i<26; ++i)
+    //     {
+    //         newvalues[2*i+0] = char('a' + i);
+    //         newvalues[2*i+1] = char('A' + i);
+    //     }
+    // }
+    // ibuf.swap(newvalues);
+    //
+    // Info<<nl << "after swap:";
+    // printInfo(ibuf);
+
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //