Load KML, find nearest locations based on long, lat

* /:map to return the KML file
* /locations/:map to return nearest locations in KML data from the
user's current longtitude and latitude based on IP.
* /locations/:map/:address to return nearest locations in KML data
from the input address. This address is geocoded into long and lat.
* /locations/:map/:long/:lat to return nearest locations in KML
data from the input long and lat.
* All routes except the KML file support a `fields` query to filter
the response from the route. See `json-mask` module for details.