Base template

django-knowledge documentation ( http://django-knowledge.readthedocs.org/en/latest/customize.html#if-you-have-your-own-template-shim-wrapper ) mentions a KNOWLEDGE_BASE_TEMPLATE setting that does not exist in source code.

This patch allow user to customize base template. KNOWLEDGE_BASE_TEMPLATE's default is django_knowledge/base.html .

inner.html template now extends BASE_TEMPLATE template variable, which is passed in views.
I considered to pass this variable to the template using a context processor, but it has several drawbacks like asking user to append it in his configuration file.