Quick fix to also exclude 'undefined' as strings'

Add compact function to prevent undefined/falsy keys in the peer list. They are a side-effect of an existing issue where peers try to connect with an undefined key, so this code will be removed once that issue is fixed.

Update peer list port.

Go back to using original peerjs-server module.

Remove network checking, because PeerJS should now be better about handling network connectivity issues: https://github.com/peers/peerjs/pull/217

Move logs to logs directory.

Shorten the network check interval to 1/2 maxNoHelloTime.

Stop checking if the peer is there once we remove it from the network.

Now on port 9002, with a longer network check interval.

Quick fix for when we try to kill already missing peers' sockets.

Merge pull request #1 from ScholarNinja/resilience

Use own fork of peerjs-server, adapted to allow for HELLO type messages. Add interval-based network checking to purge stale peers. This is necessary because our main clients, extensions, have no way of getting into the extension lifecycle and signaling to the server that they are about to leave, e.g. when a browser shuts down.

Experiment #3

HELLO pinging

Network check experimentation