Implement Hot Reloading

[snowbldr]

This might be possible with spliffy using this middleware https://github.com/webpack-contrib/webpack-hot-middleware

This would allow us to write an fntags hot reloading middleware.

Some inspiration for how to do that can likely be found in one of these two react hot reloading middlewares
https://github.com/gaearon/react-transform-hmr/
https://github.com/gaearon/react-hot-loader