Absolute URLs for links appearing in feed

note that this changes the oft-used byline()
Adding changes to subscriptions_controller and subscriptions index.html.erb
Issue 2249: Clarifying errors on Prompt Memes
Adding tests to check prompt meme error notice
Issue 2215: Error 500 on GE Summary page
Issue 2215: Adding tests
issue 3459: Humanize model names in errors
Issue 3459: Adding test
Fix broken dl and div HTML and add translation strings on owned_tag_sets/show
Warnings, categories, and ratings should be comma separated on the tag set's show page
Bring it up to date with master so maybe I won't get an error on the associations page
Issue 2969: Published Date on works not respecting time zone preference
Issue 2969: Changed how original date is computed.
Issue 3494: Moderators can delete PromptMeme sign-ups
Issue 3494: Now with tests
Migration that modifies indexes per issue 3297, adding a composite index on work-id / position and remove a duplicate work_id index
Database Changes for issue 3428, remove unneeded indexes
3778 Status of nominations lies about ability to edit or delete
Partially Reviewed can be edited but not deleted
I don't remember that being there for Reviewed, but okay