Use EventSource instead of websockets

[estrattonbailey]

https://developer.mozilla.org/en-US/docs/Web/API/EventSource

[barelyhuman]

Based on existing experience, this ends up adding a little more lag in the live reload as compared to the web socket, while the websocket is a little more un-reliable without a few patches.

A simple fix might be the retry mechanism available from the following post
https://adamcoster.com/blog/create-a-live-reload-server-for-front-end-development