Readme documentation updated

Here comes our documentation proposal for your project.

This work has been done by Julien Moulin, Stéphane Mangin, Robin Collet and Maxime Meunier, as part of our MIAGE software development project.

This work  has been supervised by Mathieu Asher.
We think it could help to better understand your work on the PCM project.

Bets regards,