Note: this commit is part of reorganizing some of the recently
imported R packages, which are being reimported into more appropriate
categories (and removed from math) as a result of a recent discussion
on tech-pkg and privately with wiz@. See the thread starting with:
http://mail-index.netbsd.org/tech-pkg/2014/09/05/msg013558.html
plyr is a set of tools that solves a common set of problems: you
need to break a big problem down into manageable pieces, operate
on each pieces and then put all the pieces back together. For example,
you might want to fit a model to each spatial location or time point
in your study, summarise data by panels or collapse high-dimensional
arrays to simpler summary statistics. The development of plyr has
been generously supported by BD (Becton Dickinson).
