Adds code to merge place polygon and points using:

Adds code to merge place polygon and points using:
  label relation member
  admin_center, admin_centre relation member (with same name)
  exact name, search_rank and location match

Adding this requires a new column and index:
  SELECT AddGeometryColumn('placex', 'centroid', 4326, 'GEOMETRY', 2);
  CREATE INDEX idx_placex_linked_place_id ON placex USING BTREE (linked_place_id);