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In a few rare cases (eg, polyMesh::resetPrimitives) it has been
replaced by an autoPtr.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

@@ -111,7 +111,7 @@ void testMapDistribute()
     }
 
     // Construct distribute map (destructively)
-    mapDistribute map(constructSize, sendMap.xfer(), recvMap.xfer());
+    mapDistribute map(constructSize, std::move(sendMap), std::move(recvMap));
 
     // Distribute complexData
     map.distribute(complexData);