TRUNK-4901 Scheduled orders cannot be discontinued
* add Order.isActivated()
* add Order.isActivated(Date)
* fix issues introduced by switching isFuture with isStarted/!isStarted for
orders scheduled in the future
** Order.isActive(Date) of stopped orders scheduled for the future were
considered active
** Order.isDiscontinued(Date) of stopped orders scheduled for the future which
were not considered discontinued
* add OrderService tests to ensure we can revise orders scheduled in the
future and that the original orders are considered discontinued
* add OrderService tests to ensure we can discontinue orders scheduled in the
future
