Send a buffer as data

I am trying to send `Buffer` as data into the queue, enabling the corresponding mode in Redis.
However after looking at the code for `kue` I found that there are multiple places where `JSON.Stringify` is used to convert the `Buffer` into an `Object`. Any plans for a new feature?

Start by tracing the multiple JSON.stringify calls mentioned in the issue and how jobs are stored and read through Redis. Check how Buffer values are currently converted, then define done as sending and retrieving a Buffer without converting it into a plain object while preserving existing job data behavior.

Written by the indexing model from the issue text.