Added more tests including network tests

I added more test methods, including testing the face registration and interest methods. I used the gevent library (http://www.gevent.org) to run threads with two faces on localhost.

It's not that it bothers me, I just don't know exactly what it is doing.  I think the test cases should be run automatically by python (or nosetests wrapper), using which one would specify the desired tests and verbosity... Unless I'm missing something