Fix shuffle for arrays with ndim > 2: added a allow_nd as an acceptable parameter to resample.

Fixes https://github.com/scikit-learn/scikit-learn/issues/3694 by passing allow_nd=True into check_array within resample and shuffle, allowing shuffle and resample to work on arrays with ndim > 2. Also added a short test for shuffling an array with ndim = 3.
spaces after commas would be more style-conformant, and there should be two spaces before `#`