ENH: remove reliance on the Xfer class (issue #639)

This class is largely a pre-C++11 holdover. It is now possible to
simply use move construct/assignment directly.

In a few rare cases (eg, polyMesh::resetPrimitives) it has been
replaced by an autoPtr.

applications/test/mesh/Test-mesh.C

@@ -91,7 +91,7 @@ int main(int argc, char *argv[])
                 runTime,
                 Foam::IOobject::NO_READ
             ),
-            Xfer<pointField>(points),
+            std::move(points),
             shapes,
             boundaryFaces,
             boundaryPatchNames,