Display gzipped size for JS and CSS after builds

[gaearon]

We currently recommend http-server for testing prod builds but it doesn’t gzip.
This might lead you down the path of optimizing the wrong thing in the bundle size.
We should fix our instructions.

[gaearon]

Actually: we should display gzipped build size for JS and CSS assets after compilation.

npm run build should print it. It has access to Webpack stats.

[gaearon]

If you’d like to work on this please write a comment here. This is up for grabs!

How to Contribute

[lvwrence]

I'll take this!

[ForbesLindesay]

We could recommend st for serving the files. It's a pretty fully fledged node.js static file server with gzip enabled by default.

[gaearon]

Thanks for the suggestion! I’ll use that instead.

[gaearon]

Hmm, st has some caching issues: isaacs/st#73.
I’ll probably have to back out of that.

[insin]

Next candidate: https://github.com/scottcorgan/pushstate-server ? 😼

[gaearon]

Okay, pushstate-server looks great so far: gzip, good defaults, no aggressive caching.
Updated the instructions to use it instead.