[CHORE] Only adding business rules if we need them (no empty tags).
[CHORE] Not rendering shipping address in request if not provided.
[CHORE] Removing subscription id and auto-renew unless provided.
[FEATURE] Created new 'store' method for creating subscriptions.
[CHORE] Updating API version for SOAP URL.
[CHORE] Removing new 'store' method and using modified 'create_subscription' method instead.