Support local service discovery BEP 14

[RangerMauve]

I've been having trouble getting clients to seed to each other either on the same machine or on the same network (on a home network).

Another concern is that the reliance on the DHT / Trackers means that you can't discover peers if you're not connected to the internet at large.

Would a PR that adds support for BEP 14 be welcome?

[epvbergen]

I'm also very interested in that functionality. However can it work? If webtorrent runs on top of webrtc, local discovery using multicast requires that the browser-based webrtc can join multicast addresses using SDP. Or something in that vein. I've looked at the specs but there's no indication that that is even a thing... I so dearly hope I'm missing something and don't need to bundle some kind of service that would need to be installed.

[RangerMauve]

Yeah, I think the local discovery would only work in node.js. :(

[pataquets]

I would love to see this implemented, too.
Even when not working under WebRTC, lots of NodeJS projects use this lib.
This one could benefit, for instance: mafintosh/torrent-stream#204
Big +1 here.

[pataquets]

@feross Any feedback about @RangerMauve offer? (Or somebody else)

[feross]

Really nice PR to solve this issue from @hicom150 here: #48