Add supplementary group support and fix sudo functionality.

Created the the ability to add supplementary groups by specifying the following in the environment:
          "groups": [
            "www-data5",
            "root",
            "developer4"
          ] 

Fixed the sudo functionality. It was creating an entry in /etc/sudoers.d/user but there was no include in /etc/sudoers to include stuff in /etc/sudoers.d/

Tested fine on Debian 7.2 and Ubuntu 12.04