Fixed #16074 -- Added ContextMixin to class-based generic views to handle...

Fixed #16074 -- Added ContextMixin to class-based generic views to handle get_context_data. Thanks emyller, Luke Plant, Preston Holmes for working on the ticket and patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17875 bcc190cf-cafb-0310-a4f2-bffc1f526a37