Issues/18 sleep while jobless

This PR works however (messy);

Why don't we add this variable (and possibly others) to the DoctrineOptions to provide all and any defaults for each (named) queue

Then before creating the queue we merge the DoctrineOptions with $config['slm_queue']['queues'][$requestedName], effectively allowing to override any option you would want to override per queue. 

This would allow the flexibility to eg. create a queue as sqlite in memory (unittest or 'on the fly' image resizing, you wouldn't mind loosing jobs) and a more persistent one (sending newsletters).

An hydrator could set all options on the queue... or a $this->setOptions() might work