Please add silhouette functionality to RBBGCMuso

[zbarcza]

In this context silhouette means an ensemble of simulations that sweeps the entire output variable space for a Monte-Carlo based experiment. The output can be a plethora of gray curves for e.g. LAI or GPP that shows all possible annual curves. The functionality can be used to highlight incorrect parameterization or improper parameter intervals. It can improve the quality of the optimization process by visual inspection.