Complete PHP/Cake e-commerce system

A PHP/Cake system for licencing and payment of a Cloud-based service has been partially implemented and needs completing. The payment mechanism is via Paypal. The work to be done includes:

- License expiry check needs to be implemented to determine if a license has expired (now > end_date) and reset the membership field in the user table.
- REST method to create a trial membership needs completing. This will not use the Paypal trial system as we do not require users to give payment credentials.
- Stateless logins need implementing to secure access to create_trial REST call.
- Log file management and log web-view.
- Notification emails.
- Other tasks TBD.