Updating the changes to be backwards compatible with django 1.8

Author: lakinwecker

select2/models/descriptors.py

@@ -1,7 +1,10 @@
 import django
 from django.db import router
 from django.db.models import signals
-from django.db.models.fields.related_descriptors import ReverseManyToOneDescriptor
+try:
+    from django.db.models.fields.related import ReverseManyRelatedObjectsDescriptor as ReverseManyToOneDescriptor
+except ImportError:
+    from django.db.models.fields.related_descriptors import ReverseManyToOneDescriptor
 from ..utils import cached_property
 
 

select2/widgets.py

@@ -10,6 +10,11 @@
 except ImportError:
     from django.forms.util import flatatt
 from django.utils.datastructures import MultiValueDict
+try:
+        from django.utils.datastructures import MergeDict
+except ImportError:
+        MergeDict = type('MergeDict', (object, ), {})
+
 from django.utils.html import escape, conditional_escape
 from django.utils.encoding import force_unicode
 from django.utils.safestring import mark_safe
@@ -205,6 +210,6 @@ def _has_changed(self, initial, data):
 
     def value_from_datadict(self, data, files, name):
         # Since ajax widgets use hidden or text input fields, when using ajax the value needs to be a string.
-        if not self.ajax and isinstance(data, (MultiValueDict)):
+        if not self.ajax and isinstance(data, (MultiValueDict, MergeDict)):
             return data.getlist(name)
         return data.get(name, None)