Enfilade!

[Eric Dean Tribble <tribble>]

My canonical editing of "Hello Not Quite So Bogus World" works again
in Enfilades.  The big difference is that it's a splay-tree based
enfilade, and it uses virtual subtrees.  That means I have one bottom
crum per span, rather than per atom.  Partial Orgls will use almost
exactly the same implementation as virtual subtrees.  After I
implement partiality in enfilades, I'll start rebuilding the ent!

Hi ho, hi ho...

dean