I made several fixes to the 3d the multi resolution data selection
support. Everything should work properly at this point.

The specific changes made were:

   a) I added a view area to the multi resolution data selection
      since the frustum and cell size were insufficient in 3d.
   b) I corrected an issue with the multi resolution operator getting
      the wrong data limit for the first render in 3d.
   c) I enhanced the MRTest reader to provide a 3d mesh.



git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@22589 18c085ea-50e0-402c-830e-de6fd14e8384