No bug - implement preprocess.sh functionality in Python.
No bug - include argparse for Python versions older than 2.7.

argparse is included with Python 2.7 and older.  ci.mozilla.org uses a
version of Python older than 2.7.  Therefore I'll include a version of
argparse and use it in this environment.
No bug - implement preprocess.sh functionality in Python. r=rnewman