passed :ascii_only in all to_json methods as my tests show Apple only supports ASCII json (JSON containing UTF-8 characters – which is valid JSON – fails silently)
modernised the gem using the guide at https://github.com/radar/guides/blob/master/gem-development.md
removed dependancy on the original 'apns' gem by downloading and adding the file from https://raw.github.com/jpoz/APNS/master/lib/apns/notification.rb (as of today)