Refactored and Packaged (w/ testing)

problems + fixed:
* templates/invoice.html and css/invoice.css do not persist during: python setup.py install, even despite including a data_files directive in setup.py. After inspecting the setup.py sdist, the problem does not appear to occur for pip (solved by MANIFEST.in)

* added scrits/envois to setup and migrated from bash to py

* specific locale EN not found on ubuntu -- commented out the line for now