Fixes test file re mapping BL title/maintitle to CSL volume-title/title
Fixes test file re mapping BL title/maintitle to CSL volume-title/title

Fixes mapping BL=biblatex title/maintitle fields of @book, @collection, @proceedings, @reference (incl. mv variants) entries to CSL volume-title/title variables; instead of the *incorrect* CSL title/container-title.
jkr/pandoc-citeproc,jgm/pandoc-citeproc,adunning/pandoc-citeproc