fixing an issue with the  wich was /usr/local/bin /usr/bin /bin /usr/local/games /usr/games... (-_-)
changing /bin/sh => /bin/bash
Revert "fixing an issue with the dev_path variable wich was path... (-_-)"

This reverts commit e1555984187b0ee5a0b49f8019a09978b13733ce.
renaming the backup_script, and adding a short description of it in the README.md file
modifying some stuff in the licence disclaimer