Process coastlines differently

[dianashk]

There are many errors about name tags missing for coastline areas. Maybe just set name to "coastline"? These could also go into a separate file, if it makes sense to break them out since they aren't administrative, but rather natural.

{
  "message": "Area is missing a name tag",
  "data": {
    "type":"Feature",
    "properties": {
      "natural":"coastline",
      "boundary":"administrative",
      "admin_level":"4"
    }
  }
}