C++ will jovially select the implicit conversion operator, even if it's
complete bogus, such as for unknown-size types or non-destructible
types. Therefore, all such conversions (which incur a copy) must
(unfortunately) be explicit so that non-copyable types continue to work.
This is generated by GenerateLocaleData, which will soon be in the
Locale namespace. Move it out of CurrencyCode.h, as that will continue
to live in the Unicode namespace.
This data is published under ISO-4217 as an XML file. Since we can't
parse XML files yet, and the data isn't very large, it was translated to
C++ manually here.
