Make this repo working with binder

I've made some changes to make this repository working with binder :

• Define all the requirements (requirements.txt)
• Fix issue with the figures directory (must exist to save generated figures)
• Define a python runtime to make it more reproducible (runtime.txt)
• Add a button on the README to run the notebook on BinderHub
• Modify the link behind the binder-run-button in order to match this repo and not my fork.

There is some modifications you might want to check. the Pearson correlation coefficient is slightly different from the one you got (the difference is like 14 numbers after decimal point). It might be because I've run the notebook on linux with a different version of python. Using mybinder force the notebook to be run in the same environment which is cool but you might want to check the publication to have the same numbers 😄