Update Members to use proper APIs

[JustinSainton]

The least of which should be the WPSC_Purchase_Log API.

When recurring orders are added to the database, they don't currently trigger any of the order_status hooks. They should do this (as well as triggering their own hooks).

Came across this due to a support request, asking if recurring subscriptions for physical products would send the product shipment info to Shipwire. See wp-e-commerce/WP-e-Commerce#2077