feat: fixes after testing with noisier data (#2)

* print a warning to console when invalid coordinates are present in dataset.
* rename cli to __main__ to allow calling as a python module
* move data validation to `io` module

geocluster/encoding.py

@@ -64,8 +64,8 @@ class GeoJSONEncoder:
                 "cluster_id": cluster_id,
             }
 
-            lon = props.pop("lon")
-            lat = props.pop("lat")
+            lon = float(props.pop("lon"))
+            lat = float(props.pop("lat"))
 
             point = geojson.Point((lon, lat))
             self.state.append(geojson.Feature(geometry=point, properties=props))