More descriptive error messages

[TorrentofShame]

Error messages (ie: 400: Bad Request) should contain messages describing what caused the error (except for sensitive information).

For example, when the client sends an invalid JSON doc, the server should return an error payload like so:

{
    "code": 400,
    "name": "Bad Request",
    "description": "The browser (or proxy) sent an invalid JSON document."
}

The server should also detail what field caused a validation error to occur (ie: sending fields of the incorrect datatype)