Update version to 0.6.4

Bugs fixes
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* typos in README.rst
* w3c validation

Cleaning
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* Code factorisation (models.py, views.py)
* Usage of the documented API for models _meta in auth.DjangoAuthUser

Whats new
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* Add powered by footer
* set warn cookie using javascript if possible
* Unfold many to many attributes in auth.DjangoAuthUser attributes
* Add a github version badge
* documents templatetags

Update to version 0.6.2

As it do not work with django 1.7