Machine learning functionality - clustering (Issue #34)

[HussainAther]

I've created the file 04r__n170_clustering.py with the clustering methods on N170 EEG data. This should be converted using sphinx to be added to the documentation.

Thanks for your help!

[HussainAther]

I should clarify: I've commented out some of the clustering methods because, on my computer, I keep running out of RAM every time I try to run those methods. If you could test them out and see if they'd work, feel free to uncomment them. Otherwise, everything else should be good to go.

The manifold methods we discussed (Riemmanian folding, TangentSpace, diffusion depth embedding, etc) are in another file in the '.zip' I've shared on Mattermost.