Support for 7.1 and multichannel streams

[theotherjenkutler]

Hi.
I was wondering if this would even be possible on an icecast2 server.

[toots]

It should definitely be possible using the %ffmpeg encoder. The radiofrance code has support for it I believe: https://github.com/radiofrance/rf-liquidsoap/blob/master/scripts/transcoder/formats/hls.aac.liq#L57