Add Websocket support and a few other changes

[andrewheadricke]

This PR adds WebSocket as a new connection method. It also adds WebSocket as a connection option in the testing index.html page.

It also adds support for v3 messages, and fixes a small console error when syncing messages returns null/empty.

I have a Meshcore BLE -> WebSocket proxy utility I will upload in the next day or two that this works with. Why? Because my browser does not support WebBLE and my Meshcore companion firmware only supports BLE.

[andrewheadricke]

This tool https://github.com/andrewheadricke/meshcore-proxy enables WebSocket access to Meshcore radios. It is very handy. And is why I created this PR. WebSocket access to Meshcore opens up more access for web apps to communicate with Meshcore.

[liamcottle]

Hey @andrewheadricke,

Thanks for the update, and apologies for taking so long to reply. It's been very busy in the mesh world!

Unfortunately at this time, I wouldn't be willing to accept websocket client support in the official library as this is not natively supported in the firmware.

If we end up adding websocket support to the firmware, I'd be willing to accept it in the library.

I'll close this one out for now :)