mozilla/butter — pull request #840 by secretrobotron (2012-08-21 18:22:03+00:00)
Title: [t2057] Rewrote target highlighting

1. Removed position-tracker and code which depended on it.
2. Updated target.js.
3. Supplied small amount of css (less) to take advantage of new highlighting strategy.
4. Rewrote a lot of page-element to not use an extra highlight element, and did some clean-up along the way.