Output T0 correction figures

[MilanKlausz]

Similarly as for the MCPL input filtering, where --figure_output input option can be used to visually verify the TOF filtering range (and Gaussian fitting), a similar option could be implemented for the T0 correction Gaussian fitting.

Either use a separate input option (with new names), or use a unified one (just make sure that the script in only terminated when both figures are created).