Replaced the 'operatingsystem' fact evaluated during the installation and configuration of Puppet with the 'osfamily' fact which makes this module also work on Ubuntu. Updated the README accordingly.
Use the same fact-scope for 'osfamily' as in install.pp and also provide a proper case for 'default => undef' to prevent running into the error 'No matching value for selector param 'undef'.
Merge pull request #1 from eliasp/ubuntu-support

Added support for Ubuntu.