Support BibTex shortauthor and an equivalent for yaml

[John-Toohey]

When citing organizations it is not uncommon to want to abbreviate their name (e.g. "BBC" for "British Broadcasting Corporation"). In BibTex this is implemented through the shortauthor field. To my knowledge, There is no recognition of this field in Hayagriva and no equivalent in the YAML representation.

As for the YAML representation, a possible solution could be to change the type of a person to allow input something akin to:

# ...
  author:
    name: British Broadcasting Corporation
    shortname: BBC
# ...

Or, equivalently for an array of authors:

# ...
  author:
    - name: British Broadcasting Corporation
      shortname: BBC
    - Doe, John
# ...

If this feature is already implemented and I am just being inept I apologize.

Nevertheless, thank you overall for this piece of software. Should my proposal be desirable I can try my hand at implementing it.