Adjust Websocket-over-HTTP example to work out of the box

[viktorvsk]

Hello! I've recently found out about pushpin and I have an idea where it could become a great fit.
I was learning a protocol and javascript examples didn't work out of the box for me.
I've adjusted one of them to make it work out of the box for me.

I can see 3 reasons why it didn't work:

1. I have a wrong understanding of how protocol/js-grip works — then please guide me to understand where am I wrong
2. Something is wrong with examples either because they don't reflect current NodeJS or anything else — then probably a fix to example could be merged after a review and a bit of a polishing
3. Something is wrong with js-grip package — if so, hint me out what exactly could be improved and I would love to open a pull request for that