New Trace UI

This is a re-write of the main trace UI. I'll get an example up soon.

With this re-write all generation happens server side. Once rendered, we use flight to add behavior to the page. The page is rendered as styled divs instead of via d3. The page will now take up the full width of the browser, popups are also larger and clearer. Individual spans can be expanded and collapsed. Filtering of services has been simplified and expanded as well.