* Removes dependency on lsb-release and/or Facter >1.7
(values are based on $::lsbdistcodename, when available)
* Simplifies maintenance: only lib/facter/util/* require updates as new
releases are made
Caveats:
* apt::codename is removed; to override debian_* facts, set the
FACTER_debian_codename environment variable for puppet
* If tracking unstable, make sure lsb-release is installed, as other
methods can't tell between testing and unstable
