add weasel + piggieback

I came across this tweet today: https://twitter.com/swannodette/status/365272360896569344

> @swannodette
> bonus points for anyone who writes a WebSocket based ClojureScript REPL for this project template

assuming that project template refers to mies, I think this is a start! :)

things like a quick start guide in the README, maybe an easier way to start up the weasel REPL are forthcoming if you'd like those