views: respond with GeoJSON (#3)

GeoJSON[1] is the standard way of representing geo entries.  Return a
GeoJSON Feature from lookupId and FeatureCollection from lookupKey,
lookupToken, lookupBounds, and lookupAround.  The key/ value pairs
from PlaceToken are stuffed into properties.

[1] http://www.geojson.org/geojson-spec.html

Helped-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Ashok Gautam <ScriptDevil@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>