Issue #2955404 Mixed Content Error
Issue #2990417 Incorrect variable name on configuration
Issue #2986821 Skimlinks API changed. Removed form validation.
Clears allowed domain cache when domains are updated
Skips domain update when CURL error occurs
Skips domain update when API response code is not 200
Stops cron before hitting rate limit of 40 requests per minute (within same process)
Stops cron process when 406 response code is returned (hit API rate limit) - see http://developers.skimlinks.com/merchant.html – this could occur if cron is run in more than one process and/or run more than once per minute.