Allowed for a null value for author
Added model tests for commentaries.
Added commentaries rather than commentary as possible url for commentary list
Write view tests for commentary objects.  Closes #21
Made author conditional on commentaries, added date of publication
Created a new function to generate the best link for a publication.
Added schema.org metadata to commentary articles
Added a test fixture for commentary objects
Added google authorship link to commentary page.  Part of issue #46