Send preloaded data to client

[Rich-Harris]

Rather than the initial page doing preload on both server and client, the server should send the preloaded data with the client app, so that it's unnecessary.

[EmilTholin]

Do you think the preload data should be sanitized, like e.g. in the Redux documentation?

JSON.stringify(preloadedData).replace(/</g, '\\u003c')

Or maybe something like serialize-javascript should be used?

[Rich-Harris]

@EmilTholin excellent point — serialize-javascript seems like the right choice, I went with that. Thanks for the rec.

Closed via #87