Add a Layout for North-South so that it is visible in the GUIs

From Broadridge: Current cutter technology produces dual single stacks (not a single slit-merged stack).  This is sometimes called a North-South layout (A-M on the left side and N-Z on the right side), so that one stack is placed on top of the other to form a complete job. To solve this, we used afpReorder (which has the "north-south" option to create "parallel columns"). We add a custom step for afpReorder with the "-p2" parameter:  

-p2     = pages 1 to n/2 and (n/2)+1 to n in parallel columns

And for duplexed job, a custom formdef, based on F1N2SS12, to place the partitions correctly:

/*page 1*/      PLACE 1 FRONT                                                  

/*page 2*/      PLACE 2 FRONT                                                   

/*page 3*/      PLACE 2 BACK                                                   

/*page 4*/      PLACE 1 BACK ; 

Therefore, a North-South option should be added to the available Layouts. One other customer had the same issue.