ENH: add alternative STL ASCII parsers

- In addition to the traditional Flex-based parser, added a Ragel-based
  parser and a handwritten one.

  Some representative timings for reading 5874387 points (1958129 tris):

      Flex   Ragel   Manual
      5.2s   4.8s    6.7s         total reading time
      3.8s   3.4s    5.3s         without point merging

applications/test/surfaceReading/Make/files

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

applications/test/surfaceReading/Make/options

@@ -0,0 +1,6 @@
+EXE_INC = \
+    -I$(LIB_SRC)/fileFormats/lnInclude \
+    -I$(LIB_SRC)/surfMesh/lnInclude
+
+EXE_LIBS = \
+    -lsurfMesh

applications/test/surfaceReading/Test-surfaceReading.C

@@ -0,0 +1,145 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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/>.
+
+Application
+    Test-surfaceReading
+
+Description
+    Test basic surface format reading capabilities (and speeds)
+
+Note
+    The filename extensions are used to determine the file format type.
+
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "Time.H"
+#include "clockTime.H"
+#include "triSurface.H"
+#include "MeshedSurfaces.H"
+#include "UnsortedMeshedSurfaces.H"
+#include "STLReader.H"
+
+using namespace Foam;
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+int main(int argc, char *argv[])
+{
+    argList::addNote
+    (
+        "Test basic surface format reading capabilities (and speeds)"
+    );
+
+    argList::noParallel();
+    argList::addArgument("inputFile");
+
+    argList::addBoolOption
+    (
+        "triSurface",
+        "Use triSurface for read"
+    );
+    argList::addBoolOption
+    (
+        "triFace",
+        "Use triFace instead of face"
+    );
+    argList::addBoolOption
+    (
+        "unsorted",
+        "Use UnsortedMeshedSurface instead of MeshedSurface, "
+        "or unsorted output (with -triSurface option)"
+    );
+
+    argList::addOption
+    (
+        "ext",
+        "name",
+        "Force alternative extension"
+    );
+
+    argList::addOption
+    (
+        "stl-parser",
+        "N",
+        "ASCII parser type: 0=Flex, 1=Ragel, 2=Manual"
+    );
+
+    #include "setRootCase.H"
+
+    const fileName importName = args[1];
+
+    word ext;
+    if (!args.readIfPresent("ext", ext))
+    {
+        ext = importName.ext();
+        if (ext == "gz")
+        {
+            ext = importName.lessExt().ext();
+        }
+    }
+
+    args.readIfPresent("stl-parser", fileFormats::STLReader::parserType);
+
+    clockTime timing;
+
+    if (args.found("triSurface"))
+    {
+        triSurface surf(importName, ext);
+
+        Info<< "Read surface:" << endl;
+        surf.writeStats(Info);
+        Info<< "Area        : " << sum(surf.magSf()) << nl << endl;
+    }
+    else if (args.found("triFace"))
+    {
+        MeshedSurface<triFace> surf(importName, ext);
+
+        Info<< "Read surface:" << endl;
+        surf.writeStats(Info);
+        Info<< "Area        : " << sum(surf.magSf()) << nl << endl;
+    }
+    else if (args.found("unsorted"))
+    {
+        UnsortedMeshedSurface<face> surf(importName, ext);
+
+        Info<< "Read surface:" << endl;
+        surf.writeStats(Info);
+        Info<< "Area        : " << sum(surf.magSf()) << nl << endl;
+    }
+    else
+    {
+        MeshedSurface<face> surf(importName, ext);
+
+        Info<< "Read surface:" << endl;
+        surf.writeStats(Info);
+        Info<< "Area        : " << sum(surf.magSf()) << nl << endl;
+    }
+
+    Info<< nl << "Reading took " << timing.elapsedTime() << "s" << nl
+        << "\nEnd\n" << endl;
+
+    return 0;
+}
+
+// ************************************************************************* //