Make django-balanced compatible with python 3

[foxwoods369]

I also opened a ticket regarding updating to python 3 on balanced-python: balanced/balanced-python#75. I'm opening this up to gauge interest in updating this package. In addition to the dependency on balanced-python, there's other dependencies that are incompatible with python 3, such as an old version of simplejson when there's a new version which is compatible with python 3.