Fix edition version numbers after unpublishing

Unpublished editions will decrement their major/minor sensibly.

Also added a data migration to reset *all* version numbers in an attempt to plug up any holes that have appeared from being published, unpublished, and republished.  The data migration is based on the original migration used to give all editions a version number.  It does leave some inconsistencies with how things would be had they been managed via the system instead of forced though, there's a comment on the commit explaining that.

https://www.pivotaltracker.com/story/show/42955489