• #87: add dependency on tqdm, add read_csv_cached
• #81: remove dependency on blockdiag
• #66: add dependency on patsy in requirements-dev.txt for new content

Add content for machine learning #55, #54, #47.

First release after refactoring the package.

• #24, #25, #26, #27, #28, #29, #30, #31, #32, #33, #34, #35, #36: ajout d'exercices existants
• #22: ajout d'un exemple sur le Mathador
• #21: refactoring