
Currently, in validate_zip_code() it is not checked if the number of digits
in the Zip Code is exactly 5, as this number is not the same in all countries;
as an example, in New Zealand, Zip Codes consist of 4 digits, not 5.
A better solution could consist of choosing the Country on the signup form
and hence allowing a wiser validation.
Maybe this could allow to avoid two different links for Signup
(Italy) - (Outside of Italy).

In shopping/templates/purchase_confirmation.ihtml the current date format
is not dependent on the shop administrator's preferred language;
maybe it should be chosen in application-??.inc.php.

