Update CDN and Scout links to HTTPS

There were a few links to Scout I updated to `https://`.

More importantly, I updated some links to CDN resources to be HTTPS, so that an all-HTTPS site like Scout can load them properly without mixed content warnings. They'll work fine like this for a non-HTTPS site as well.

I've re-run `gulp`, so it should have updated the `dist/` directory correctly. I have not published to S3.