clean
There's a bug in the backend API where the GeoJSON can contain data that isn't part of the tile for example the 16/32277/21812.json contains MultiPolygons for the University of Law, University of Bristol, and Monarchs Way walking route. This strips out Features that someone has wrapped giant polygons around in the original OSM data. Need to see if there is a fix for this on the backend...
Return
String representing the cleaned tile.
Parameters
tile
Slippy tile X.
tile
Slippy tile Y.
zoom
Zoom level should be 16.0
geo
String that represents the tile.