In preparation for the systematics

Now the output TFile are created by the Eff library, and no more by the calling makePlots macros.

The min_events parameter is now set by command line and no more in the config files: this will allow to modify the binning (for the adaptive case) avoiding to create almost identical config files which only differ by a number, and only creating new rules. Of course, this is pointing to the direction of not using wildcards for the systematics of the efficiency...