We now display inherited props properly after adding a Property
Properties now sort alphabetically in Edit

It turns out that, although TreeMap is sorted, and TreeMap.zipWithIndex
produces another TreeMap, the resulting TreeMap is *not* sorted the same
way.  So you need to explicitly re-sort it, sadly.
Fixed another bug in Edit/Create sorting
You can now trash any property in Edit

It's a little messy, but we can now remove unwanted Properties.  This, I
think, brings Edit to the point where it now really works right.