Adds possibility to map alpha3 to alpha2 code

Currently the country-code automatically detected by the site is a three
letter code. Therefore current users will always see an 'Unknown
Country' when they try to see alist of Usergroups. To show them lists in
their country I've added a mapping between 3- and 2-letter code
Merge pull request #36 from heiglandreas/feature/addCountryCodeMapping

Adds possibility to map alpha3 to alpha2 code

* heiglandreas/feature/addCountryCodeMapping:
  Adds possibility to map alpha3 to alpha2 code