move preen cron to migratin
move progress-pollyfill to require for performance
set lower default tokens
some more comments in preen_users, 7 days
move preen_users to real cron (remember to setup on the server with crontab)
cupdate store.coffee accessControl methods to new (accept, err) callback signature of racer (coincides with https://github.com/lefnire/derby-auth/pull/19)