Handle flat tree, cleanup relationship between views, interpretation of sections

* Accomodate flattened tree structure
* Handle new interpretation hierarchy
* Partial views code is streamlined
* Chrome views delegate to partials
* Add handler for interpretations of sections, paragraphs, and appendices
* JS for updating the header now includes section number and appendix letter
* Refactor handling of "sectional" links to have few levels of indirection
* LHS TOC links now work in "sectional" mode
* Internal citations to comments now use the correct "sectional" url