Add nMigen to docker & chroot images.
* New: In bootsrap/docker: * install python3/nMigen tool in all environment. * Add a new image on top of the coriolis one to have a shell (with X11 connexion to the host system). * Upgrade Yosys to 0.9. * Correct integration of allianceInstaller.sh in socInstaller.py. * Add a chroot mode to socInstaler.py (for Debian 9 chrooted). * Allow benchs to be run separately.