Collin:  Thanks for taking the time to look at this.

I don't think this change is worth making.  I've started working on some new features in minidom and it seems like every time I exercise a new piece of code, the gc finds a small number of objects in cycles.  For example, parseFragmentString() seems to leave a few objects (even with expatbuilder.second.patch).  We're just going to have to live with it--  I don't think anyone has time or desire to hunt down them all down.