Fixed case where json.loads() accepted a string integer.

json.loads("1") will actually return 1, so we need to check that
an iterable is returned.

Added skeleton code for dealing with playlist submissions.

Added skeleton code for volume up and down.
Fixed "BAD MESSAGE" when playlists are broadcasted without rqid.
Removed msg_success dependency on message rqid as parameter.

This will remove the necessity of having to remember to add rqid
as the parameter to a msg_success/msg_fail.

Fixed syntax bug.
Fixed bug where it's possible to pause music before actually
playing.

Cleaned up non-essential arguments.