Initial fixes to make the debug-toolbar to work with Python 3 using six from django.utils

Hello,

I made these initial fixes at PyCon to start porting the debug-toolbar to Python 3. I'm basically using `six` from `django.utils` I run the tests but it fails in the SQL panel. The debug-toolbar loads fine in Django 1.5 with python 2.x but in Python 3, the SQL content is missing.

I'm pushing this request if somebody else would like to help and If this is the way you guys would like the changes.

Thanks!