FIX: Setting account group.

1. If UserAccount and GroupAccount are defined, set the UID and GID and restrict the supplemental groups to only that GID. This means you get one UID and one GID. No supplemental groups.

2. If UserAccount is set and NOT GroupAccount, then call initgroups to restrict the groups to those that the user is a member of including the group mentioned in /etc/passwd.
DOC: clean license files.