Bring back date/country columns in tables

See for example http://test.musicbrainz.org/area/e1c1215f-dcc0-35b4-b840-d2ca2151593b/releases?page=55 where the countries are all over the place because the length of the date changes.

We don't combine the label and catalogue numbers into a single column despite them being in pairs, so I see no reason why we've done it for the dates and countries.