[feat] add plot=FALSE option to plot() to export data

[SciLiciumTheo]

Thanks for this package.

This PR is to add the option plot = FALSE (default plot = TRUE) to plot() export the plot data instead of actually plotting, reproducing behavior of e.g. base R hist function.
This is helpful for people wanting to have finer control over what/how to plot, or using plotting engines other than base R (for example ggplot2), without adding dependency to such libraries.