adds a BibEntry object to the works cited list even if not cited
with a call to citep/citet
Usage
record_as_cited(entry)
Arguments
entry
a BibEntry object (or something that can be coerced to one, like bibentry)
Value
Adds the object to the citation list, with a BibTex citation
key that does not duplicate any that are already in the record.
Invisibly returns the bibentry object.