Enhance error message

[gildesmarais]

Should say "as required in your consume specification".

Violations:
{
  "users -> brewster": [
    {
      "error": "ERR_MISSING_REQUIRED",
      "message": "The published object has an optional property that you marked as required in your specification.: [\"street\",\"city\",\"state\",\"postal_code\",\"country\",\"paypal_address\"]",
      "location": "users::payment_information"
    }
  ]
}