This reverts commit 7c125138.

Various changes from the "redesign" branch

See merge request ift/nifty-dev!78

See relevant error message below:

$ python nifty-dev/demos/getting_started_1.py
[…]/python3.6/site-packages/nifty5/utilities.py:227: FutureWarning: Using a non-tuple sequence for
multidimensional indexing is deprecated; use `arr[tuple(seq)]` instead of `arr[seq]`. In the future this will be interpreted as an array
index, `arr[np.array(seq)]`, which will result either in an error or a different result.
  np.add(tmp.real, tmp.imag, out=res[slice1])
[…]/python3.6/site-packages/nifty5/utilities.py:239: FutureWarning: Using a non-tuple sequence for […]
  np.subtract(tmp[slice2].real, tmp[slice2].imag, out=res[slice1])
[…]/python3.6/site-packages/nifty5/utilities.py:243: FutureWarning: Using a non-tuple sequence for […]
  _fill_upper_half(tmp[dim1], res[dim1], axes2)