Look up DOI (for node creation) on CrossRef by author/title

This adds another flow to create a biblio node. After searching by author/title, it lists the matching citations with the DOIs linked to auto-fill the DOI creation form. The matching citations are not formatted in any significant way, but all of the data is displayed in period-delimited form (to resemble citation styles). This required some changes to the form-related hooks so that it would repost to the initial page rather than always progressing to the second page.