Add roll_median

[mdancho84]

Looking for a rolling median roll_median function. Doesn't look like the most recent CRAN version includes this. Let me know if you are interested in adding.

Thanks, Matt

[peleonard]

@mdancho84 I wrote a package about roll_median. You can try if you like.

[jasonjfoster]

Thanks for the feedback. I think a more general development is to create a rolling quantile function where min, max, and median are special cases. Would be a nice enhancement.

[jasonjfoster]

I have added roll_median in the development version:

# install.packages("devtools")
devtools::install_github("jjf234/roll")