Plus reorganise tests

Validation is based on wikipedia list of postal codes [1]. Formats were
converted into regexes for countries.

1: http://en.wikipedia.org/wiki/List_of_postal_codes

Fixes #753

Also I moved the generate_hash fn up to the Address superclass as it's
possible that it might be used in other Address classes.

Also split them into unit and functional tests.

to the admin and model set-up.

Completed the models for the order package too.  Added admin files