Add up-voting of queued tracks

[orangespaceman]

Anyone can queue a track, and once they're queued you can't specifically re-order them, but can vote for ones you like. With an up vote, a track will move to the top, or at least above any tracks without an up vote. When there are multiple tracks with up votes, and the more up votes a track has the higher it jumps in the queue. Any track can only be up-voted once by each user