#64 Allow reassign on delete in Admin routines

[Eric Vaandering]

For some admin routines, it might make sense to allow
re-assigning associations before the delete takes place.

For instance, when deleting a document type, it might
make sense to allow all documents of that type to be
re-marked as being of another type before the delete
takes place.

Or when deleting security groups, perhaps all users who
are part of that group should be reassigned to another
group.

Basically, this is consolidating and then deleting.