Add "total time" of currently queued songs

[marcossoria]

Lot of people create a queue for a shorter temporary playlist. For example if you know you'll run for 40 minutes or drive for 30, choose the songs you want to listen to instead of a bigger playlist. It would be very helpful to know what the total time of the queue is when you add songs to know if you've got enough or too much for the time you are going to listen to. Can be small and almost unnoticeable!