the "tack on the leftover tasks at the end" step of the "circular dependency sort"

the "tack on the leftover tasks at the end" step of the "circular dependency sort"
makes a copy of those tasks with the circular_parent marked.  this way the tasks
do not iterate through their child items polymorphically, which is necessary because
the "circular sort" stores individual subclass tasks separately (i.e. saving/deleting
should not traverse polymorhically for those tasks)