The length of revision.rev_comment was not correct for the MySQL DDL
Fixed the WikipediaLoader's generator for the 'watchlist' table. We now have a cap on the max number of entries that each user could have. Previously a user could be watching as many pages as there were in the database. This was obviously unrealistic. I also switch the empty page restriction field to be just 'none'. This was originally needed for Oracle but now it's the same across all DBMSs.