Add task spooler (linux) support as an alternative to the queue

[adenbley]

I encode on a headless machine and sometimes need to switch computers I'm using to access FastFlix (or need to turn off a laptop) . For this reason I use task spooler by copying the raw command to it.

It would be nice if FastFlix could send jobs to tsp, even better would be to show the tsp jobs in the queue, and best would be to also show the status of the current job.