ENH: improve consistency in version handling (issue #1010)

- use std::string instead of c-string for the string constants

- centralize some definitions of resources into foamVersion.H

  Now expose some of the hard-coded values used in foamEtcFiles()
  so that they can be known or even overridden as required.

  Relocate to src/OpenFOAM/include as a constant location.

src/fileFormats/ensight/file/ensightGeoFile.C

@@ -24,7 +24,6 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "ensightGeoFile.H"
-#include "foamVersion.H"
 #include "macros.H"
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
@@ -39,9 +38,9 @@ void Foam::ensightGeoFile::initialize()
 
     // Description line 2
     #if OPENFOAM
-    write("Written by OpenFOAM-" STRING_QUOTE(OPENFOAM));
+    write("Written by OpenFOAM " STRING_QUOTE(OPENFOAM));
     #else
-    write(string("Written by OpenFOAM-" + string(foamVersion::version)));
+    write("Written by OpenFOAM");
     #endif
     newline();