Remove attributes that are not needed when caching

the Response object. This fixes #346

rest_framework/response.py

@@ -45,3 +45,13 @@ class Response(SimpleTemplateResponse):
         # TODO: Deprecate and use a template tag instead
         # TODO: Status code text for RFC 6585 status codes
         return STATUS_CODE_TEXT.get(self.status_code, '')
+
+    def __getstate__(self):
+        """
+        Remove attributes from the response that shouldn't be cached
+        """
+        state = super(Response, self).__getstate__()
+        for key in ('accepted_renderer', 'renderer_context', 'data'):
+            if key in state:
+                del state[key]
+        return state