Feature Request: histogram instead of density kernel

[Jadamso]

Thank you for a great package.

For some cases, it would be helpful to use a histogram rather than a kernel density. The ability to use R's hist function and breaks argument would be very easy to use. This functionality is also not currently available via ggplot.

[TomKellyGenetics]

Thanks for the suggestion, this requires a significant overhaul of the source code but I agree it would be possible to use this package a foundation to implement this. I'm unsure whether it is best to set up a new parameter with an "if" statement or if it is better to create a new function for back-to-back histograms. The "split" parameter would also allow for bihistograms to be created in R.

I'm open to accepting pull requests if you have time to implement this yourself.

[TomKellyGenetics]

Addressed in open PR #18