Fix the event that gets emitted when ProxyRoom connects
Clean up handoff process; Add proxied handoff via USR2

* Master: Properly send and load headers and UUID for sockets being transfered
* Master.Stream: Move uuid handling to Sources.Base
* Mode.Master: Add support for proxied handoff via SIGUSR2
* Sources.Base: Set uuid internally
* Icecast: Add support for passing in uuid at creation