Include semi-supervised learning in the map

[robert-lucente]

We exchanged tweets about adding semi-supervised learning in the map. It was recommended that I add an issue.

[robert-lucente]

Perhaps ideas from the following mind maps might be helpful?

Tour of Machine Learning Algorithms by Jason Brownlee
http://machinelearningmastery.com/a-tour-of-machine-learning-algorithms/

Choosing the right estimator at scikit-learn
http://scikit-learn.org/stable/tutorial/machine_learning_map/