Update group.py

 PEP 3110 -- Catching Exceptions in Python 3000
Update validators.py

 PEP 3110 -- Catching Exceptions
Fixing test invocation to work with Django 1.7.
Update tests to use latest dot releases of Django.
Adding Python 3.3 to the automated test suites.
Merge remote-tracking branch 'refs/remotes/origin/pr/1'
Convert doctest suite to use Manuel instead of sphinx-build.
Strip ``u`` characters from string output when testing on Python 3.
Fixes for tests failing on Python 3.