ISO 3166-3 for formerly used codes

[jari604]

Great that you made these files. Really usefull to combine many data sources on their country codes.

I sometimes use older datasets for instance from the 70's were different country codes were used for certain countries. This is all shown in https://en.wikipedia.org/wiki/ISO_3166-3.

It would be great if these former codes were present in the dataset as well, including a column to show in which countries they were changed or split. Also shown these former codes behind the new countries.

Maybe also include ISO 3166-2 for subregions as well?
https://en.wikipedia.org/wiki/ISO_3166-2