Add support for Geolite Country local SQL DB.

lib/generators/geocoder/maxmind/geolite_city_generator.rb

lib/generators/geocoder/maxmind/geolite_country_generator.rb

...tors/geocoder/maxmind/templates/migration/geolite_city.rb

...s/geocoder/maxmind/templates/migration/geolite_country.rb

lib/generators/geocoder/maxmind_generator.rb

lib/geocoder/lookups/maxmind_local.rb

lib/geocoder/results/maxmind_local.rb

lib/maxmind_database.rb

lib/tasks/maxmind.rake