Improve Welsh counties/unitary authorities

These are actual used counties, as opposed to historic counties
Refs: http://en.wikipedia.org/wiki/Subdivisions_of_Wales and http://www.ons.gov.uk/ons/guide-method/geography/beginner-s-guide/administrative/england/counties--non-metropolitan-districts-and-unitary-authorities/map-of-the-uk-counties-and-unitary-administrations.pdf
Add welsh translations