Use last channels & co versions

- Use last official releases of channels, asgiref, daphne and
  asgi-redis packages.
- Customization of JsonWebsocketConsumer is now in kfet app through a
  custom class (and so, doesn't require anymore a forked version of channels).
- Clean kfet consumers code.

kfet/consumers.py

@@ -1,26 +1,21 @@
 # -*- coding: utf-8 -*-
 
-from __future__ import (absolute_import, division,
-                        print_function, unicode_literals)
-from builtins import *
+from django.core.serializers.json import json, DjangoJSONEncoder
 
-from channels import Group
 from channels.generic.websockets import JsonWebsocketConsumer
 
-class KPsul(JsonWebsocketConsumer):
 
-    # Set to True if you want them, else leave out
-    strict_ordering = False
-    slight_ordering = False
+class DjangoJsonWebsocketConsumer(JsonWebsocketConsumer):
+    """Custom Json Websocket Consumer.
 
-    def connection_groups(self, **kwargs):
-        return ['kfet.kpsul']
+    Encode to JSON with DjangoJSONEncoder.
 
-    def connect(self, message, **kwargs):
-        pass
+    """
 
-    def receive(self, content, **kwargs):
-        pass
+    @classmethod
+    def encode_json(cls, content):
+        return json.dumps(content, cls=DjangoJSONEncoder)
 
-    def disconnect(self, message, **kwargs):
-        pass
+
+class KPsul(DjangoJsonWebsocketConsumer):
+    groups = ['kfet.kpsul']