Fix bug 936127: Add new tracking events across site.

Also removes some JavaScript that was repeated (merge error at some 
point, doh) and fixes some indentation.
Merge pull request #92 from Osmose/ga-tracking

Fix bug 936127: Add new tracking events across site.
Fix Bug 932526: Update HP Video
Fix Bug 930298: Add scroll GA tracking.
Merge pull request #89 from bensternthal/930298enhance-ga

Fix Bug 930298: Add scroll GA tracking only.
Fix bug 939304: Add basic skin to 404 and 500 pages
Small tweaks from feedback on bug 930298.