[src] updated MultivariateGaussianCharacteristicFunction: made comparisons of
results with lebrun's branch before removing the module in the
MultivariateRandomMixture
[src] Removed the use of MultivariateGaussianCharacteristicFunction module for the computation of multivariate normal characteristic functions
[src] minor cosmetics : reorganized the methods using alphabetic order
[src] added get/setPDFPrecision methods to better contol the runs
[test] updated the R^3-->R^2 use case with input uniform distributions. Added graphical plots for illustrations
[test] updated the R^3-->R^2 use case with input gaussian distributions : replaced surface plots per contour plots
[test] updated graphical pdf
[test] added graphical pdf