Django-websocket-redis3

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* created 1 requirements file under ``examples/chatserver/requirements.txt``
* renamed chatclient.py to test_chatclient.py - for django-nose testrunner
* migrated example project to django 1.7
* edited ``docs/testing.rst`` to show new changes for using example project

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* Added method ``release()`` to ``RedisSubscriber`` and calling this method each time a Websocket
closes, for whatever reason. This should avoid some reported memory issues.

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* Fixed: **django-websocket-redis** failed to initialize under some circumstances in combination
with Django-1.7. This only happened for logged in users and threw this exception:
``django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.``
* Added setup on how to run **django-websocket-redis** with uWSGI but without NGiNX.

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* Message echoing can be switched “on” and “off” according to the user needs. Before it was “on”
by default.
* Many changes to get this app compatible with Python3. This is still not finished, since the
pilfered module ``websocket.py`` is not PY3 compatible yet.
* Added a class ``RedisMessage`` to pass and store the message to and from the websocket.
Before this was just a string with serialized data.

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* Fixed: ``request.user.username`` has been replaced by ``get_username()``.

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* Messages can be sent to users being member of one or more Django groups.
* ``RedisPublisher`` and ``RedisSubscriber`` now only accept lists for ``users``, ``groups`` and
``sessions``. This makes the API simpler and more consistent.
* A new magic item ``ws4redis.redis_store.SELF`` has been added to reflect self referencing in
this list, what before was done through ``users=True`` or ``sessions=True``.
* Added the possibility to receive heartbeats. This lets the client disconnect and attempt to
reconnect after a number of heartbeats were missed. It prevents silent disconnections.
* Refactored the examples.
* Added reusable JavaScript code for the client.
* Added a context processor to inject some settings from ``ws4redis`` into templates.