get_author_list doesn't handle organizations

[RobLBaker]

get_author_list only returns authors that are individuals and does not handle authors (creators) that are organizations. Improve get_author_list to include organizations as well as individuals.

[RobLBaker]

Currently waiting on test data packages that have creators as authors in the expected format so that this code can be developed/tested.

[RobLBaker]

Waiting guidance on authorship: some DOI policy may preclude organizational authorship.