Figure out how to cache / store / update snippets better

[bahmutov]

Need to cache / refresh scripts better without always loading them from the server.
See https://stackoverflow.com/questions/12291138/how-do-you-inspect-the-web-inspector-in-chrome and localStorage solution.

[bahmutov]

Code snippets - open dev tools, you can see the individual snippets cached inside localStorage.scriptSnippets

[bahmutov]

Fetching and updating snippets stored in the localStorage working, need to describe.
See update-code-snippets.js