ENH: distributedTriSurfaceMesh: work with flipped shells. Fixes #2405

Two problems:
- flipping inside snappyHexMesh is not done in a parallel
consistent way. So e.g. the octree-cached inside/outside information
has already been calculated. For now flipping of
distributedTriSurfaceMesh is disabled.
- octree-cached inside/outside information was using already
cached information and would only work for outwards pointing
volumes

tutorials/mesh/snappyHexMesh/distributedTriSurfaceMesh/system/snappyHexMeshDict

@@ -38,6 +38,11 @@ geometry
         file "box_trans.obj";
         type distributedTriSurfaceMesh;
     }
+    shell
+    {
+        file "box_scaled.obj";
+        type distributedTriSurfaceMesh;
+    }
 };
 
 
@@ -129,6 +134,12 @@ castellatedMeshControls
 
     refinementRegions
     {
+        shell
+        {
+            // Refine a volume
+            mode    outside;
+            levels  ((1.0 6));
+        }
     }