Fixes for SxS in Notices

* Remove prtpage, ftref, and su tags
* Keep full text, including any E tags
* Child logic now includes what might be a "sibling" if it doesn't specify section
* Do not include "empty" analyses in the sxs layer
* Remove "text" field from sxs layer; 1.5M -> 8.6K change in file size
* Properly label "Appendix A"-style headings
* Handle analyses of interpretations