testcases working

nifty/data_objects/my_own_do.py

nifty/operators/fft_operator_support.py

nifty/operators/laplace_operator.py

nifty/operators/power_projection_operator.py

nifty/spaces/power_space.py

nifty/sugar.py

test/test_field.py

test/test_operators/test_composed_operator.py

test/test_operators/test_diagonal_operator.py

test/test_operators/test_fft_operator.py

test/test_operators/test_laplace_operator.py

test/test_spaces/test_power_space.py