[poppler] New entry for "programs using poppler"

[Jeroen Ooms]

Would it be possible to mention the R package 'pdftools' [1] on the
poppler website [2] under programs using poppler? The R package quite
popular among (data) scientists to extract text and data from pdf
documents such scientific papers or public records.

[1] https://cran.r-project.org/package=pdftools
[2] https://freedesktop.org/wiki/Software/poppler