get_access_token module is not included in PyPI packages #192

I'm not sure if I'm missing something, but the get_access_token module doesn't seem to be included in either the .tar.gz or .whl in the 2.0 release on PyPI.

A cursory glance at setup.py shows that modules are included using find_packages(), which won't include .py files in the root according to this.

Without get_access_token, I'm unable to authenticate my application with Twitter.