Optimize plotting of overlaid lines #301
Description
#300 introduces a multiple_lines function in order to plot multiple lines with the same properties onto the same plot all at once (via 2d array input) in order to make plotting faster. Not at all a priority because I am quite sure the optimization we can get with that will probably not be noticeable for plots that compute stats like kde/hist/ecdf but it might be worth keeping in mind for other plots
For plot_parallel as there are no computations it can make quite a difference as using the fast or slower version can change perception between instant or non-instant plotting, plot_ppc won't be instant mostly due to the kde. But when plotting thousands of overlaid lines it might still be noticeable to some extent