Bandaid for bug in which disconnected user isn't removed from channel

* When user tries to enter a song, isConnected will check to see if any used channels are "used" by that user. If so, it frees those channels (since obviously they wouldn't be used as the user is trying to enter the song at that time).
Merge pull request #30 from artfoundry/channel-clearing-fix

Bandaid for bug in which disconnected user isn't removed from channel