Updating README.md with info on branches/distros
Use puppet labs' base box for Debian 7.3 (x64)

Note: No Virtualbox extensions in this one.
Provisioning is completely without error though, unlike Ubuntu
Remove failure warning, does not happen in Debian
No need to handle ubuntu user on debian branch
Merge branch 'debian_7.3-lxde' of github.com:gandaman/franca_install_automation into debian_7.3-lxde