[py3] Replaced basestring by six.string_types.
[py3] Replaced basestring by six.string_types.

gchp/django-formtools,lastfm/django-formtools,lastfm/django-formtools,thenewguy/django-formtools,gchp/django-formtools,barseghyanartur/django-formtools,barseghyanartur/django-formtools,thenewguy/django-formtools