Experimentalist Consistency

[chadcwilliams]

There is still some variations between the experimentalists, especially with what they return. Most of them (maybe all except the assumption experimentalist, which needs updating) will return a pandas DF when given conditions as a pandas DF. But the behaviour varies when providing conditions as a numpy array. For example, when getting an np.array as input, the novelty sampler outputs a pandas DF, but the falsification sampler outputs a np.array. In the tutorial we explicitly state that experimentalists MUST output a pd.DF, and I think we should adapt the experimentalists to do this no matter the input. You'll notice in the first 2 basic tutorials that there are discrepancies in the code when dealing with different experimentalists because of this and it is confusing.

[chadcwilliams]

Let's highlight this problem in the tutorials. i.e., rely on pandas arrays, especially as outputs but in general.