``norm=backward``, ``forward`` keyword options for ``numpy.fft`` functions
--------------------------------------------------------------------------
The keyword argument option ``norm=backward`` is added as an alias for ``None``
and acts as the default option; using it has the direct transforms unscaled
and the inverse transforms scaled by ``1/n``.

Using the new keyword argument option ``norm=forward`` has the direct
transforms scaled by ``1/n`` and the inverse transforms unscaled (i.e. exactly
opposite to the default option ``norm=backward``).