Improve on Readme

[CDieterich]

Hi @AminaLEM

please try to imagine that you are a first time user.. the first thing I would like to know is what this readme is about.

What is the purpose, what is the input, what steps are taken and what will be the output.

Please explain right in the beginning.

Users might also be interested in typical use cases.. the term predict for example IMHO does not involve retraining, but refers to the application of an existing model.. However, this does not seem to be the case.

One purpose is to reproduce the results of the paper end-to-end..

Another keyword is generalization.. how would a user move on to use different data and reapply existing models.

Please proceed along these lines.