-Codechange: renamed all 'schedule' stuff to 'order(list)'
-Codechange: moved all order-stuff to order_cmd.c / order.h
-Codechange: vehicles that share orders are now linked to eachother
with next_shared/prev_shared in Vehicle
Developers: please use AssignOrder to assign data to an order. If not,
you _WILL_ make the save-routine to assert!