Added prefetch data but keeping off github
Added prefetchData handler
Added try/catch for JSON circular error
Added opts.noFilter option
Embedded spinner into index.html

This will get the spinner on the screen sooner during initial load.
Changed to individual external file version

Now we’ll just track versions per-file to reduce user data loads when
some parts don’t change.  I.e. the vendor.js file should change much
less frequently than the app, partial or css files.
Re-use instructor cached data now instead

Before, this page would reload the instructor data, now it only
refreshes the cache.