MB-87: Update RoyalMail Worldzones

[brideo]

27

https://meanbee.atlassian.net/browse/MB-87 http://www.royalmail.com/international-zones

Royalmail now don't support Non EU countries what so ever. This update will mean our module replicates the current delivery methods Royalmail do.

I also removed the Non EU zone from the tests and a few models. I updated the getWorldZone() method within the Helper to use a switch statement as it's a bit more legible and thats what the rest of the module uses.

[tgerulaitis]

Approved :+1:

[joolswills]

Without this fix, there is no international signed available to some countries like Russia, Turkey and others - might be an idea to merge it into master and tag a new release as users may not realise that the last tagged release is broken.