[dev-biblio] take 1 on CSL mods

OK, here’s a possiblity, where i only allow two-levels:

 <bibliography author-as-sort-order="first-author"

author-shorten-with="———.">
<use-et_al min-authors=“4” use-first=“3”/>

References

Primary Sources

Published Sources


Unpublished Sources



Secondary Sources










I still need to think on this more and see if I can make this more
automated; e.g. whether I should standardize the published/unpublished
groups as a grouping category, and therefore have the software
automatically handle that.

Bruce