ENH: suppress Info output for some cases (issue #722, #893)

- add additional control via a Foam::infoDetailLevel flag, which is
  supported by a 'DetailLevel' macro.  Eg,

      DetailLevel << "some information" << nl

- When infoDetailLevel is zero, the stdout for all Foam::system() calls
  are also redirected to stderr to prevent child output from
  appearing on the parent.

- close stdin before exec in system call.

applications/utilities/miscellaneous/foamListTimes/foamListTimes.C

@@ -124,7 +124,7 @@ int main(int argc, char *argv[])
     {
         if (nProcs)
         {
-            // Info<< "Remove " << timeDirs.size()
+            // Serr<< "Remove " << timeDirs.size()
             //     << " processor time directories" << nl;
 
             forAllReverse(timeDirs, timei)
@@ -153,7 +153,7 @@ int main(int argc, char *argv[])
         }
         else
         {
-            // Info<< "Remove " << timeDirs.size()
+            // Serr<< "Remove " << timeDirs.size()
             //     << " time directories" << nl;
 
             forAllReverse(timeDirs, timei)

applications/utilities/surface/surfaceMeshInfo/surfaceMeshInfo.C

@@ -122,7 +122,7 @@ int main(int argc, char *argv[])
     const scalar scaling = args.lookupOrDefault<scalar>("scale", -1);
     if (scaling > 0)
     {
-        Info<< " -scale " << scaling << nl;
+        DetailInfo << " -scale " << scaling << nl;
         surf.scalePoints(scaling);
     }