Add optional non standard ISO 3166 alpha-2 entries to the countries.
Add optional non standard ISO 3166 alpha-2 entries to the countries.

Make it possible to include non standard ISO 3166-alpha2 codes like EU
for the European Union to the countries array returned by
BTBookingCountries::get_countries().

Buschtrommel/BTBooking,Buschtrommel/BTBooking,Buschtrommel/BTBooking