Support multiple authors on a post

[tfidfwastaken]

Description

Currently this theme allows for only one author per post, but sometimes we have multiple people writing one post.

My guess is that the files we need to mess with to allow multiple authors are:
_includes/article-info.html and _includes/article-footer.html.

Probably involves using the template's looping construct, and add to a list the authors needed and display from that list.