Improve the binomial fit use by TEfficiency::Fit by setting the correct chi2 and number of degree of freedom.

Add function in Fitter to set number of fit points and fit type. When the fit type is a binned likelihood fit used as chi2 value to report 2 * minFCN

Fix also the copying of the TF1 object after fitting. Use IsA()->New() instead of copy constructor which will not work correctly for TF2 and TF3 objects