Set WebSocket.binaryType to "arraybuffer".

By default if binary data is received on a WebSocket it is handed to the
client script as a DOM Blob object, which must be read asynchronously.  If
the binaryType option is set on the WebSocket then binary data is handed to the script
behind an ArrayBuffer interface instead, which can more easily be read and decoded
on the fly.

With this change in place, I've successfully added Fressian support to chord.  I figured you probably don't want to have the base chord package rely on additional dependencies for Fressian in both Clojure and Clojurescript, so I put it in a separate package, now available here:  

https://github.com/thinktopic/chord-fressian

Thanks for a nice library that just works.