Populate the table of countries

Meets minimum requirements for the #/countries view:
  * Queries geoname.org for countries data
  * Caches the data
  * Tabulates country name, country code, capital, area in square
    kilometers, population, and continent code
  * Formats the area and population with commas after every third digit
  * Provides a link to the country detail view for each country
  * Provides a button that can be used to return to the home view