add missing non-Standard fields to Location

[JochenSeifarth]

As per https://developers.facebook.com/docs/graph-api/reference/location/#overview the type Location has more fields than currently included in
com.restfb.types.Location

It would be great if the missing fields could be added. I'm particularly interested in city_id and country_code as I'm using them.

I.e. add

@Getter
@Setter
@Facebook("city_id")
 private String cityId;

@Getter
@Setter
@Facebook("country_code")
private String countryCode;

to com.restfb.types.Location