added forgotten check to ensure that the path_to_python in windows dev setup actually exists and print an informative warning if the user messes up somehow
added forgotten check to ensure that the path_to_python in windows dev setup actually exists and print an informative warning if the user messes up somehow

Caoimhinmg/PmagPy,lfairchild/PmagPy,lfairchild/PmagPy,Caoimhinmg/PmagPy,Caoimhinmg/PmagPy,lfairchild/PmagPy