Normalize errors

[jpadilla]

Parse's error handling and error codes aren't the best but we should definitely make them more useful.

Current implementation of normalizeErrorResponse() looks for the errors key in the payload, it if it doesn't find it it'll return:

[
  {
    status: `${status}`,
    title: "The backend responded with an error",
    details: `${payload}`
  }
];

I think the least we cold do is return whatever payload is in our normalizeErrorResponse. Thoughts?