Cleanup of duplicate and unused scripts/code/comments
Use protocol-neutral URLs
Fixes interactive scrolling into the footer

The behavior described in [#49854249] was partly due to the un-pinning of the interactive being fixed to the top of the related-content div. On many pages, that div is never rendered, so the interactive never reached the bottom of its track. Adding a dummy div to mark the bottom of the scrolling track, which is always in the DOM, fixes the issue.

https://www.pivotaltracker.com/story/show/49854249
A little documentation of the interactive pinning
Pin waypoints to a fixed div, not one that moves

It turns out that it's not a good idea to use a div which is going to be fixed as a waypoint: http://stackoverflow.com/a/10448000/306084

If we calculate the waypoint based on a normally-scrolling div (like the main content div) then a browser resize doesn't foul up the location of the trigger point.

[#49854383]

https://www.pivotaltracker.com/story/show/49854383
Whitespace: fixing JS style