Only error responses have a status property

[bertday]

Error responses from the API have a status property, e.g. 404:

{
  "status": 404,
  "error": "Not Found",
  "message": "Could not find any addresses matching query.",
  "details": {
    "normalized": "12345 MARKET ST",
    "query": "12345 market st",
  "search_type": "street"
  }
}

However, good responses don't have a status. This means that client apps can't write logic such as:

if aisResponse.status == 404:
   // do something

since status doesn't always exist.

This should probably be consistent across all cases -- either by including a status on good responses, or by always sending back HTTP status codes in the headers. The former sounds more convenient.