add python requirements for running tests

These requirements can be installed by issuing the following command at the
root of the project:

    $ pip install -r requirements.txt

In the event that you do not have pip you can obtain it via easy_install:

    $ easy_install pip

Or apt-get:

    $ apt-get install python-pip
Merge pull request #10 from t3hh00d/pip-requirements

add python requirements for running tests