Express migration + website caching

I am recommending this code be merged with the main branch immediately. We have discussed it a lot on the dev group. I just tested a javascript alert in client.js, which was immediately displayed on the first reload (reload button only, no shift required). I also changed the text and the change was again displayed on the first reload.

This tells me the new caching mechanism is recognizing when the files have changed. I believe this proves our code changes will be recognized immediately.
This `load` should also be deleted.  Just `play` seems to work.