Simulates the process of installing a package
and then attaching it. This is a key part of the 'devtools' package as it
allows you to rapidly iterate while developing a package.
Authors:
Hadley Wickham [aut],
Jim Hester [aut, cre],
Winston Chang [aut],
RStudio [cph],
R Core team [ctb] (Some namespace and vignette code extracted from base
R)