Temporary rename
Renamed to Changes and reformatted as per CPAN::Changes::Spec
Renamed CHANGES to Changes and formatted as per CPAN::Changes::Spec
Moved LUHN.pm to lib/Algorithm/LUHN.pm
Switched to Dist::Zilla

And while doing so:
    - add "use warnings"
    - dropped use of "use vars"
    - set min perl version to 5.6.0
Added github repo to pod
Added SEE ALSO section with links to other LUHN modules
Improved doc for is_valid(), in response to RT#43842