ENH: cleanup autoPtr class (issue #639)

Improve alignment of its behaviour with std::unique_ptr

  - element_type typedef
  - release() method - identical to ptr() method
  - get() method to get the pointer without checking and without releasing it.
  - operator*() for dereferencing

Method name changes

  - renamed rawPtr() to get()
  - renamed rawRef() to ref(), removed unused const version.

Removed methods/operators

  - assignment from a raw pointer was deleted (was rarely used).
    Can be convenient, but uncontrolled and potentially unsafe.
    Do allow assignment from a literal nullptr though, since this
    can never leak (and also corresponds to the unique_ptr API).

Additional methods

  - clone() method: forwards to the clone() method of the underlying
    data object with argument forwarding.

  - reset(autoPtr&&) as an alternative to operator=(autoPtr&&)

STYLE: avoid implicit conversion from autoPtr to object type in many places

- existing implementation has the following:

     operator const T&() const { return operator*(); }

  which means that the following code works:

       autoPtr<mapPolyMesh> map = ...;
       updateMesh(*map);    // OK: explicit dereferencing
       updateMesh(map());   // OK: explicit dereferencing
       updateMesh(map);     // OK: implicit dereferencing

  for clarity it may preferable to avoid the implicit dereferencing

- prefer operator* to operator() when deferenced a return value
  so it is clearer that a pointer is involve and not a function call
  etc    Eg,   return *meshPtr_;  vs.  return meshPtr_();

applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C

@@ -433,7 +433,7 @@ int main(int argc, char *argv[])
             autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
 
             // Update fields
-            mesh.updateMesh(map);
+            mesh.updateMesh(map());
 
             // Move mesh (since morphing does not do this)
             if (map().hasMotionPoints())
@@ -788,7 +788,7 @@ int main(int argc, char *argv[])
             (
                 layerExtrude.addedCells
                 (
-                    meshFromMesh,
+                    *meshFromMesh,
                     layerExtrude.layerFaces()
                 )
             );
@@ -937,7 +937,7 @@ int main(int argc, char *argv[])
             autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
 
             // Update fields
-            mesh.updateMesh(map);
+            mesh.updateMesh(map());
 
             // Update stored data
             updateFaceLabels(map(), frontPatchFaces);
@@ -1074,7 +1074,7 @@ int main(int argc, char *argv[])
         autoPtr<mapPolyMesh> map = meshMod.changeMesh(mesh, false);
 
         // Update fields
-        mesh.updateMesh(map);
+        mesh.updateMesh(map());
 
         // Update local data
         updateCellSet(map(), addedCellsSet);

applications/utilities/mesh/generation/extrude/extrudeToRegionMesh/extrudeToRegionMesh.C

@@ -2470,7 +2470,7 @@ int main(int argc, char *argv[])
 
 
     // Update numbering on extruder.
-    extruder.updateMesh(shellMap);
+    extruder.updateMesh(shellMap());
 
 
     // Calculate offsets from shell mesh back to original mesh
@@ -2818,7 +2818,7 @@ int main(int argc, char *argv[])
         addBafflesMap = meshMod.changeMesh(mesh, false);
 
         // Update fields
-        mesh.updateMesh(addBafflesMap);
+        mesh.updateMesh(addBafflesMap());
 
 
 //XXXXXX