Add ACL support to the linking app, convert import to absolute

apps/linking/models.py

@@ -1,8 +1,10 @@
+from __future__ import absolute_import 
+
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
-from linking.managers import SmartLinkManager
-from linking.literals import OPERATOR_CHOICES, INCLUSION_AND, \
+from .managers import SmartLinkManager
+from .literals import OPERATOR_CHOICES, INCLUSION_AND, \
     INCLUSION_CHOICES