When revising an order, the previous order should be stopped an instant before the new one starts

Currently when you revise an order, previousOrder.dateStopped is set to the same instant as dateActivated.

This is inconsistent with the way we calculate autoExpireDate (it is set to an instant before start+duration) and the way we query for active orders (which is inclusive of stopDate).

We need to change the code so that it stops the previous order 1s before the new one is activated.