to StringHelpers.

I added ability to read nodeset enumerations from Silo MRG Trees as described
in a recent stakeholder meeting on the topic.

I refactored code supporting arbitrary polyehdra so that both 'normal' Silo
zonelists with DB_ZONETYPE_POLYHEDRON zones as well as Silo PHzonelists would
use the same code and logic to detect zoo-type zones as well as decompose
truly arbitrary zones into zoo-type zones.

Test suite should pass with these changes. I also have some tests I will
commit related to these changes later.


git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@18757 18c085ea-50e0-402c-830e-de6fd14e8384