raw_input is used to get feedback on the install
However it seems to have issues with pip. See
#59 comment from @mgedmin
A possible fix is: "abstain from asking questions with raw_input if sys.stdout is not a terminal." How to do this cross platform reliably I'm not sure.
Maybe raw_input can just be removed, and better messaging, or a separate script or command can help people configure. python setup.py configure or some such.