As per comment, this seems to be the way to make setSinkId work reliably on Chrome.
Also don't make our own mediastreams if we don't need to (ie. in a normal call
our tracks should come with their owen MediaStreams).
This does a fairly basic rewriting of the whole file to bring it up
to a vaguely modern standard of code. Nothing should have changed
fundamentally, but it probably should do: as per the global type
overrides, we use a lot of deprecated WebRTC APIs and should probably
update.
Michael Telatynski