BUG: avoid duplicate ensight surface mesh/geometries (issue #167)

- ensight does supports geometry in a separate file, but for the
  surface writer we claim that this is not true. This allows
  the field writers to control where the mesh/case files land.

  With 'true', the uncollated output would incidentally create
  things like this:

  Previous (w/ fields)        | Now (w/ fields)
  ----------------------------+----------------------
    0.05/surf.case            |
    0.05/surf.mesh            |
    0.05/p/surf.case          |  0.05/p/surf.case
    0.05/p/surf.mesh          |  0.05/p/surf.mesh
    0.05/p/surf.0000.p        |  0.05/p/surf.0000.p

  Previous (w/o fields)       | Now (w/o fields)
  ----------------------------+----------------------
    0.05/surf.case            | 0.05/surf.mesh
    0.05/surf.case            | 0.05/surf.mesh

  Move the separateGeometry() flag to the *.C code, where it is less
  likely to be mistakenly altered.

src/sampling/sampledSurface/writers/ensight/ensightSurfaceWriter.C

@@ -68,6 +68,17 @@ Foam::ensightSurfaceWriter::~ensightSurfaceWriter()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+// Note that ensight does supports geometry in a separate file,
+// but setting this true leaves mesh files in the wrong places
+// (when there are fields).
+//
+// Make this false to let the field writers take back control
+bool Foam::ensightSurfaceWriter::separateGeometry() const
+{
+    return false;
+}
+
+
 Foam::fileName Foam::ensightSurfaceWriter::write
 (
     const fileName& outputDir,

src/sampling/sampledSurface/writers/ensight/ensightSurfaceWriter.H

@@ -126,10 +126,7 @@ public:
 
         //- True if the surface format supports geometry in a separate file.
         //  False if geometry and field must be in a single file
-        virtual bool separateGeometry() const
-        {
-            return !collateTimes_;
-        }
+        virtual bool separateGeometry() const;
 
 
         //- Write single surface geometry to file.