Installs python-lxml as a newebe dependency.

Related to issue #289 .

- Add test
- Fixed Newebe's playbook failing on first run on a fresh Debian 7 VM
- Restart supervisord on changes
- Security: Use /usr/sbin/nologin as login shell for newebe user
- Speed: Consolidate all 'apt' entries into one
- Strip trailing whitespaces
- Update to take advantage of apache2_module from Ansible 1.6
- Use file path=... state=absent instead of "rm" command to delete files

/etc/apache2/sites-available and old (dangling) symlinks in
/etc/apaches/sites-enabled.
Also, remove unnecessary apache2 restart after creating a new
virtualhost but not yet enabling it.

The virtual site files must be owned by root (serious security issue)
and they must have the .conf filename suffix for a2ensite on
Ubuntu 14.04LTS (apache 2.4.7).

+ make lines < 80 chars