Speed up Jekyll builds

https://cloudcannon.com/tips/2017/12/08/speed-up-your-jekyll-builds/

Limiting # of posts

jekyll serve --host=0.0.0.0 --limit_posts 100 --incremental

3rd party thumb maker

https://images.weserv.nl/ with nice gdpr policy https://github.com/andrieslouw/imagesweserv/blob/3.x/Privacy-Policy.md

test