Add check for subreddit with live promoted links.
Spotlight option to show next/prev buttons.
spotlightlisting: move thing insertion and javascript setup to functions.
Don't use SpotlightListing to wrap links in GET_fetch_promo.
Use an ad server to select promos for spotlight.
let CampaignBuilder handle the wrapping
adzerk specific updates for spotlight
wrap in get_adzerk_promo
starting to move adzerk ids to config

NOTE: need to update example.ini
adzerk selfserve
Add impressions property to PromoCampaign.
Add hooks in promote.