Add a length of queue measurement

[MTStavros]

Sometimes I want to start a queue for something like a plane ride or a homework session, so I would like to be able to know how long the queue is. It is just frustrating creating a queue with one of the songs that I am most looking forward to near the end, then finding out that I unknowingly put it at the end of a queue that was twice the length of the time that I needed it to be.