pinned down version of mptt to 0.5.1 or 0.5.2

see django-mptt/django-mptt#207

Author: beniwohli

cms/__init__.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-__version__ = '2.3'
+__version__ = '2.3.1'
 
 # patch settings 
 try:

setup.py

@@ -32,7 +32,7 @@
         'django-classy-tags>=0.3.4.1',
         'south>=0.7.2',
         'html5lib',
-        'django-mptt>=0.5.1,<0.6',
+        'django-mptt>=0.5.1,<0.5.3',
         'django-sekizai>=0.6.1',
     ],
     tests_require=[