Document pitfalls

[andreasabel]

Hi Simon, thanks for putting out this script!

I tried to make it work for my own PDF deployment, but gave up in the end because of problems with theunicode-math package. See the builds 1-8 at https://travis-ci.org/andreasabel/agda-scope/builds for a transcript of my attempts.

These are the pitfalls I ran into, you might want to warn users of your script about them:

1. An empty install: section causes the R environment to skip the script: section.
   See andreasabel/agda-scope@6e5dd35 (build 3).
   I discovered the solution to put a bogus installation entry (echo) by chance.

2. The unicode-math package seems to malfunction (at least with xelatex) in the version the R environment is using. While it can be installed via

   tlmgr install filehooks unicode-math
   

   (see andreasabel/agda-scope@88d8fbb)
   it malfunctions:

   ! Undefined control sequence.
   l.931   \file_get:nnN
                      {unicode-math-table.tex} 
   

   There is a unresolved stackoverflow issue for that: https://stackoverflow.com/questions/55137760/undefined-control-sequence-file-getnnn-error-while-compiling-markdown-file

I did not find a workaround for this issue, thus, I abandoned the R environment and used the generic environment with manual installs of pandoc and texlive-latex via apt.

Anyhow, you might want to alert users of your script about these pitfalls.