[Rd] inconsolata font for building vignettes with R-devel

[Ben Bolker]

  Just to save someone else a few seconds of googling: when you try to R
CMD check with recent versions of R-devel and you get

* checking PDF version of manual ... WARNING
LaTeX errors when creating PDF version.
This typically indicates Rd problems.
LaTeX errors found:
! LaTeX Error: File `inconsolata.sty' not found.

 the Debian/Ubuntu solution is:

sudo apt-get install texlive-fonts-extra