Add Universal Python testing script

[nmcspadden]

This code was stolen from Munki and turned into a simple separate bash script. It takes a single argument, which is a Python version, which should correspond to the version of Python used to build the framework.

It's a fairly naive script, as it assumes it's working on a local "Python.framework" bundle built, and doesn't have a lot of safety checking beyond making sure your Python version string starts with "3." (another assumption).

I used this to test AutoPkg's python after building in all the requirements.