Allow setting job options with a job_options method on the listener

I'm loving this gem, but I need to be able to set various options (e.g. queue name, retry) per listener. I figured this was the most unobtrusive way to achieve this. I would have liked to be able to code something like:
```ruby
Wisper.subscribe(MyListener, async: true, queue: 'test', retry: false)
```
but couldn't figure out how to make this work since the options aren't saved with the Registration. Might be worth changing in Wisper.

If you have ideas for a better implementation, let me know and I'll take care of it.