Story 55029828: Fixed scrollspy not refreshing when content changes

Now monitors the scrollable content on an interval, refreshing
scrollspy as necessary. This uses an interval so that the scrollable
content changes can be detected generically.
Merge pull request #232 from reciprocity/feature/scrollspy_refresh

Fixed an issue where scrollspy wasn't being updated when content changed. InnerNav now uses an interval to check for content changes (so that it can do it generically instead of listening for specific events).