A number of improvements ...
 - Added support for all frequencies, eg 2 weeks, 3 months, etc
 - Removed hardcoding of Payment Processor Id
 - Removed hardcoding of Contribution Status
 - The eWAY gateway is determined from the payment processor id in the Recurring Contribution
 - The Net Amount and Invoice Id columns are now set in Contributions
 - Now guarantee to get the first Contribution in get_first_contribution_from_recurring()
 - Since @VinceMD added logic to make Recurring Contributions 'In Progress' I rewrote
   get_pending_recurring_contributions() to search for Recurring Contributions that are
   Pending for this Payment Processor, and then find the linked Contribution. Seems a more
   natural logic.
 - Since @VinceMD added logic to make Recurring Contributions 'In Progress' I rewrote
   get_scheduled_contributions() to search for Recurring Contributions that are
   'In Progress' for this Payment Processor, and then find the linked Contribution. More
   robust if Recurring Contributions are in various states.
 - Since @VinceMD changed the created_date logic to set the time, it no longer makes sense in
   get_scheduled_contributions() to check for an existing Contribution when that check only
   searches by date and not time.
 - Changed the logic in update_recurring_contribution() that marks a Recurring Contribution
   as 'Complete'. Now, if there is a limit to the number of instalments, it counts the number
   of Contributions, and Completes the Recurring Contribution if that count has been filled.