merged go-subscriptions-bstat into go-recurly

related to:
https://github.com/GigaOM/go-subscriptions/pull/20
https://github.com/GigaOM/gigaom/pull/5354
https://github.com/GigaOM/gigaom-plugins/pull/2684

as part of https://github.com/GigaOM/legacy-pro/issues/4055