Map link should use latitude/longitude if available

The map link generated in a location object is to the postal address not the latitude/longitude, so the map will re-geocode the location, even if there is a different latitude/longitude available. This is surprising, especially if the user has manually adjusted the location because geocoding was off.

This patch changes location_map_link_us_google to use the latitude and longitude if available. If it looks good I can look at applying it to the other countries and providers.