Move to previous state and cycle state functions, plus order commenting

Attached is a patch which adds a couple operations to Ubercart Views Bulk Operations, namely "move to previous state" and "cycle state." I also added order commenting to note the operation in orders.

We needed to retroactively apply a rule to orders, which requires that the orders be updated. Not wanting to change the orders, we decided to create a new order status in the Completed state. VBO then cycles the state, effectively triggering the rule without modifying the order.

Order commenting was added because we deleted the new order status and the reference was deleted from the order comments.