Exercise for Randomised Response

Correct src/privacy/randomised_response.py so that it takes into account the number of features and randomises all of them, so as to release a randomised version of the full data set in a way that satisfies epsilon-differential privacy.

In particular, you must take care to properly take into account the fact that each feature release counts as an additional query.

Next week we will go into the Laplace and Exponential mechanisms, and there will be a practice session with Dirk.