bbox string is a standard way of passing around bbox description over a web req. Its important we document it well.

DOCS.md

@@ -18,6 +18,7 @@ Full text search endpoint which queries the elasticsearch doc store, slightly sl
   * can also be specific to one particular dataset, for example ```geoname```
 * **bbox**: the bounding box from which you want all your results to come
   * can be one of the following comma separated string values
+    * "southwest_lng,southwest_lat,northeast_lng,northeast_lat" ```L.latLngBounds(southwestLatLng, northeastLatLng).toBBoxString()```
     * bottom left lat, bottom left lon, top right lat, top right lon
     * left, bottom, right, top
     * min longitude, min latitude, max longitude, max latitude