update south

requirements.txt

@@ -16,7 +16,7 @@ python-dateutil==1.5
 python-memcached==1.48
 djangorestframework==2.3.14
 git+https://code.grnet.gr/git/nxpy
-South==0.7
+South>=1.0.2
 celery==2.5.3
 django-celery==2.5.5
 pyyaml==3.11