Bugs/71 socket.io

Server side with related client pull request: shakyShane/browser-sync-client#7
Some progress on shakyShane/browser-sync#71.

Does not attempt to proxy WebSockets, but should work over XHR long polling with most Socket.IO setups out of the box now, thanks to proper namespacing.

I used `npm link` in my `browser-sync-client` fork, then `npm link browser-sync-client` in my `browser-sync` fork to test both sides of the stack.