This class is a set of N points x[i],y[i],zi[i] in a non uniform grid.
Several visualisation techniques are implemented, includind Delaunay triangulation.
This new class is great and an important addition to ROOT.


git-svn-id: http://root.cern.ch/svn/root/trunk@7484 27541ba8-7e3a-0410-8455-c3a389f83636