AP-224 assemblies

[Dave Loffredo]

While going through AP-224e2, I just noticed an bit of oddness about
the way that it handles assemblies.  

Right now, AP-224 mandates the use of mapped_items for assemblies
rather than the item_defined transform available in AP-203 and AP-214
and preferred (and extensively discussed) by the CAX-IF implementors.
Can anyone verify my reading on this?

It should at the very least support both to be consistent with what
the systems are currently putting out.

					     - Dave