Add option for full country name in address field, in addition to two-letter code

In the same way that provinces can have their two letter code or full name, countries should have similar option.

Unless you're in the US, the two letter codes are not familiar to the lay-person, so would be nice to have

{country_name}

that return full string of the country, and

{country}

that continued to return the 2-character code.