Add places.dossier_count (#66)

Trello: https://trello.com/c/NIF7lzQO/1141-sieve-should-calculate-and-expose-the-amount-of-times-a-place-has-been-referenced-by-all-dossier-types

gapipy/resources/geo/place.py

@@ -17,7 +17,7 @@ class Place(Resource):
     _as_is_fields = [
         'id', 'href', 'name', 'ascii_name', 'population', 'elevation',
         'latitude', 'longitude', 'bounding_box', 'alternate_names',
-        'admin_divisions',
+        'admin_divisions', 'dossier_count',
     ]
     _date_time_fields_utc = ['date_created', 'date_last_modified']
     _resource_fields = [