BUG: collated ensight not working with isosurfaces (closes #318)

- the problem arises since the various surface writers are stateless.
  The collated output format hacks around this limitation by adding in
  its own fieldDict caching (to disk).

  Now include an updateMesh() method to hook into geometry changes.
  This is considered a stop-gap measure until the surface output
  handling is improved.

tutorials/compressible/rhoSimpleFoam/squareBend/system/controlDict

@@ -52,6 +52,7 @@ runTimeModifiable true;
 functions
 {
     #include "sampling"
+    // #include "samplingDebug"
 }
 
 

tutorials/compressible/rhoSimpleFoam/squareBend/system/samplingDebug

@@ -21,6 +21,7 @@ debug
         ensight
         {
             collateTimes  true;
+            // collateTimes  false;
         }
     }