pt-osc: Option to reverse triggers after table swap

Client has requested ability for pt-osc triggers to be utilized on the _new table (after swap) pointing in the reverse direction (back to the old table). 

In other words, looking for an option so that the pt-osc triggers that are placed on a table during the run to capture incoming write traffic also be created on the _new table after the swap, pointing back to the old table. This would allow client to roll back after a pt-osc change that did not work as expected and not lose any traffic, as the traffic going to the new table (after swap) is now being routed back to the old table as well.