Revert "pulled in R source code"

This reverts commit b4b15d3af9d803c4eef3421028dad4bf2f7d610f.
Revert "Merge branch 'master' of https://github.com/TaddyLab/gamlr"

This reverts commit 5b2d5c374e7de45273e801aaaa1a2b164ab26b36, reversing
changes made to b4b15d3af9d803c4eef3421028dad4bf2f7d610f.