cache headers for static assets (and on document GET)
tests
add feedback for errors to UI - esp. too long
fix that chrome bug where it loads the doc twice
add link to about page
allow power users to force highlight lang - by supplying an extension!!!!!!
maybe start serving highlighting on the other end to save transfer on highlight.js
start using CDNs for most assets

# shared version only
some way to do announcements easily (and use for ads)
copy URL to clipboard button