Add target to setup the environment

The cookie cutter DS makefile has a solution for python: https://github.com/drivendata/cookiecutter-data-science/blob/master/%7B%7B%20cookiecutter.repo_name%20%7D%7D/Makefile

They create an environment for conda, but install requirements with pip. If conda is present, they should really be using an environment.yml and using conda to handle package installations.

... anyway, I'm having issues doing something similar for R. cygwin appears to be using an older R engine (3.1.0), which is probably something I can configure correctly with an environment variable. Additionally, cygwin doesn't have write access to the library folder. Probably need to run as administrator.