yeah, working with open fire is dangerous...
For performace reasons I've undercut the premise
to make GenNode / Record immutable. Now I'm dealing with
raw storage layout together with this quite hairy distinction
between "attribute scope" and "child scope"
In hindsight, it might have been better to implement Record
as a single list, and to maintain a shortcut pointer to jump
to the start of the attributes.
...so now the stage is set. We can reimplement
the handling of the list diff cases here in the context
of tree diff application. The additional twist of course
being the distinction between attribute and child scope
