Use adzerk only for promo requests on beta subreddits.
percentage goal for non cpm campaigns
when making request to adzerk, convert keywords to lowercase
don't log changes to adzerk objects

object retrieved with GET is missing some attributes so detecting
a change isn't easy.
cleanup some of the adzerk attributes
update PromotionLog when a link or campaign is deactivated
IsActive is based on reddit thing._deleted
better logging (with time)
keywords to lower