Point references to viewer.state to viewer.state.name
Make sure navigation knows where to find chapters.
Ensure that notes have a top property to indicate their height from the top of their page.
Somehow managed to forget to commit one of the removals here.
Pull notes from the Backbone models. Fix the insertion index.  Add getNextAnnotation/getPreviousAnnotation.
Update showAnnotation to use actual note models.
Not entirely sure why this was working before...