initial attempt at python3 support

After posting issue #15 I decided to take a stab at a port myself. I haven't done any exhaustive testing, but connecting and .get and .set work correctly in python3.3 which is what I need. While these changes seem to work fine in python2.7 and python3.3, I haven't looked at compatibility with other versions at all.

I would recommend adding from __future__ import unicode_literals to all your modules, but it's not strictly necessary so I skipped it in this branch.