Constructs a GraphMatrixNDDataset, populates it with the matrix, and uses the
supplied names for the series and the supplied objects for the categories.
Model that take a delegate model to add additional lines during
rendering (such as row sum, column sum, row mean, column mean...)
Created: 21 mars 2006 19:01:27
Gere a la main le group de bouton, car sinon, lors que le premier
bouton est sélectionné, on ne peut pas le deselection
protected List buttonList = new ArrayList();