Semantic responses for errors

[eoussama]

There needs to be a constant, predictable object that contains the data and some additional info.
Something like this:

{
    "hasError": false,
    "error": { "name": "", "description": "" },
    "data": {}
}

Errors:

• Invalid route
• Invalid ID (Invalid data type passed as an ID)
• Unknown ID (MAL ID does not match anything cached.

[eoussama]

Provide an error middleware.