For various reasons, I've decided not to include a StarShipIT
integration in version 1.0 of Lorikeet. The existing integration will
either be split out into a separate open-source app, or vendored into
the internal app that uses it at CMV.

For some reason, something in some listeners (possibly an error of some
kind) was preventing the other listeners from getting called. Scheduling
listeners using setImmediate (or a polyfill of such) rather than running
them synchronously seems to handle this.

Previously, we were saving all cards on Stripe Customer objects so that
they could be reused. This change allows a user to uncheck a "save my
payment details for future use" checkbox, and if so will perform a
Charge with the provided Token directly, which makes that token unusable
in the future.

This reduces confusion as a 'Card' and a 'Token' are distinct concepts
in Stripe's API.

This reduces confusion with 'Token' objects, which are a distinct entity
in the Stripe API.