Import unittests from old repository

Created by: Ede123

As discussed at #14 it would be nice to import the unittests from the old repository (see http://bazaar.launchpad.net/~scouring/scour/trunk/files).

Some preliminary findings:

• The unittests are run by executing testscour.py (which makes use of testcss.py and the test files in the folder unittests)
• It should be pretty straightforward to bring them back to life. I was already able to run the script with minimal adjustments. Some tests fail to execute (possibly due to Python 3 incompatibilities), apart from most tests seem to work (and to pass).