forgo PeerJS in favour of plink; add signalling server (fixes #57; fixes #52)

* log when client loses connection to host (fixes #62)
* queue messages when client is not yet connected to host (fixes #64)
update dist files
update Mario example
Merge pull request #63 from cvan/plink

forgo PeerJS in favour of plink; add signalling server (fixes #57; fixes #52)