use force_text for python3
define south migration modules.
test also with python 3.4
maxint -> maxsize.
don't use deprecated modules, update tests for py3.
py3 support is started with django 1.5+

and add py3.3 that is most popular py3 version.
force_text is already a wrapper method.
DJANGO_VERSION -> DJANGO
this travis is broken
fix travis conf.
Merge branch 'python3-compatibility'