* @brief Implementation of Visualizer::SinglePadPlot. This method takes two vectors of floats and plots them on a single pad with the requested "treatment".
* Currently supports scatter plot and overlay
* @param _v1 - vector of floats. Can represent x values for a scatter, or y values of a histogram
* @param _v2 - vector of the second type of histograms to be plotted s
* @param _out_name - name of the plot (w/o extension, that's defined by a data member [ .pdf by default ]
* @param _treatment - treatment of the plots (scatter, overlay, overlay with lines)
* @param _line - y value for which a horizontal line will be drawn