BrowserStack has fixed the error reporting for screenshots. Responses now look like:

```js
{ errors: 
   { code: 'Terminal not alloted yet, cannot process screenshot at the moment',
     field: 'id' },
  message: 'Not Found' }
```

While ``Not Found - `id` Terminal not alloted yet, cannot process screenshot at the moment`` isn't the greatest, it's certainly better than `Not Found`.

Can you send the PR for this now?