Stop puller doesn't kill ffmpeg process about multistreamer

[jprjr]

I had actually just discovered this last night!

I'm working on re-doing the process management code to properly send ffmpeg the 'quit' command instead of relying on sockexec to notice the connection is gone, which will fix this problem.

Additionally, I'm going to have each pusher get its own process, instead of having a single ffmpeg process for all outputs. Then it will be possible to add/remove accounts while streaming, stop individual outputs, and so on.

[jprjr]

So I've pushed 9.0.0 which fixes this problem - but I held off on the "stop individual processes" feature for now, I'll get that coded up in a future release.