[Developers] Normalize /aviation/airport/elevation with /location/location/geolocation

[Bryan Cheung]

Airports have an included type of location, and I'd like to normalize  
airport elevations to the geocode of the airport.  I would remove the  
property /aviation/airport/elevation once the data has been migrated -  
this might break applications using this property.  Are there  
applications that would break if I remove /aviation/airport/elevation ?