Added r-tidytext and dependencies

Added r-tidytext, r-janeaustenr, r-snowballc, and r-tokenizers.

Added r-tidyr

Initial commit

A long journey to packaging r-tidyverse. The current highest-level
packages that are successfully built are dtplyr, waldo, callr, and xml2.
A handful of others (brio, digest, praise, units, zeallot) are currently
freestanding but will become dependencies soon.