Ryan Richard 6f8f99e49b
Add demo screencast and do some cleanup in demo.md
- Note that this avoids committing the demo screencast
  file to our git history because it is 5.76 MB. We won't
  want to need to download that content on 
  every `git clone`.
- Instead the file is hosted by GitHub's CDN
2020-10-06 16:35:58 -07:00
..