compare.py not correctly handling empty bins

When running

./tnp_fitter.py compare ... configs/myconfig.json

on two datasamples to produce comparison plots, if the chosen binning for a given variable x gives the first n bins to be empty, then the yields used to fill the histograms are assigned to the wrong bins.

Here an example, were in configs/myconfig.json we use "binning": { "pt": [-20, -15, -10, -5, 0, 10, 15, 20, 25, 30, 40, 50, 60, 120],

While the correct distributions obtained by starting the binning from the first non-empty bin, e.g. "binning": { "pt": [15, 20, 25, 30, 40, 50, 60, 120], looks like: