Document the exact differences with real web components

[pimterry]

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[pimterry]

Should probably move to proper polyfillying, rather than the fairly hacky current approach. https://github.com/webcomponents/webcomponentsjs/blob/v0.7.22/CustomElements.js would be a good place to start. Note that a big part of it is polyfilling MutationObserver - could just implement in Domino (as planned) and go from there.

[pimterry]

One example limitation to the approach: no Canvas. You can't serialize a server-rendered canvas, so any drawing work is inevitably lost (in reality, it actually just explodes - Domino doesn't implement canvas.getContext)

...could maybe serialize canvases as images? Probably not worth it though.