Improve OS related lines and add .gitignore

[syKevinPeng]

Hi, When I try to run your code on Windows, there are some OS system incompatible errors related to the os.system(command) function. I replace the "make directory command" with os.makedirs() and replace "cp files command" with util.copyfile() to make your code more robust.

Also, I add python-version .gitignore.