[ENH] Lines In Hierarchy ( a little cleanup needed )

[dway at mailcan.com]

The lines are kind of nice, and this might be a good addition to the
base.

However, there are still some gribblies which show up when you collapse
an item.  Specifically, when you close an item, a vestigal line still
appears just below the item which was just closed.  This should probably
be cleaned up before this can be incorporated.