Tool for visualizing meshes read by MOAB.  This tool requires Qt v3
and VTK.  qvdual gives two views of the data, one by tag name and the
other by hierarchical entity sets (sets containing parent/child
relations with other sets).  Select either from the tree view on the
left of the window to highlight the corresponding mesh in the mesh
view.

This tool was written to facilitate research in dual-based hex meshing
operations.  The buttons below the mesh view are used for that
purpose.
