more PEP8

nifty2go/nifty_utilities.py

nifty2go/operators/diagonal_operator/diagonal_operator.py

nifty2go/operators/fft_operator/fft_operator.py

...rators/fft_operator/transformations/rgrgtransformation.py

...rs/fft_operator/transformations/slicing_transformation.py

.../operators/fft_operator/transformations/transformation.py

...operators/smoothing_operator/direct_smoothing_operator.py

...go/operators/smoothing_operator/fft_smoothing_operator.py

nifty2go/spaces/gl_space/gl_space.py

nifty2go/spaces/power_space/power_space.py

nifty2go/spaces/rg_space/rg_space.py