install rpy2 on Mac+R v 3.4.1 + virtenv

It's just pain :/ So small cheat sheet.

1) add to ~/.bash_profile
export R_HOME=/usr/local/Cellar/r/3.4.1/lib/R

2) Copy over (oh yes, facepalm) headers

cp -R /usr/local/Cellar/r/3.4.1/lib/R/include/R* /usr/local/include/

don't forget to delete them after