Added support for reverse geocoding in V3.

E.g.
  my $location = $geocoder->reverse_geocode(latlng => '37.778907,-122.39732');

See Also:
https://developers.google.com/maps/documentation/geocoding/#ReverseGeocoding
fixed up test data
Merge pull request #4 from barwin/reverse_geocoding_barwin

Reverse geocoding