* fixed a bug with verify_grad failing on the second iteration with inplace
operation (missing p.copy())
* renamed make_restet and make_broadcast_restet to makeTester and
makeBroadcastTestser (sorry OB. was about to document and I figured it would be
clearer with the real names...)

* _check_view_map will not raise an error if multiple inputs have the same id,
and one of the outputs has a view_map to one of those two inputs