I modified the multi-pass discretization of CSG meshes to process each
domain independently if the number total number of boundary surfaces is
above the internal limit. This will make if possible to handle larger
CSG meshes. I also added the class vtkCSGFixedLengthBitField in order
to make it easier to change the number of bits used by the multi-pass
discretization. I added a description of the change to the release notes.
This resolves #1793.



git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@23226 18c085ea-50e0-402c-830e-de6fd14e8384