PaginatedListView changes and minor bug fix to an error message

[jsoa]

Main thing here is that I moved the functionality of PaginatedListView to ListView as I don't see a reason for these to be separate. The PaginatedListView, when paginate_by is set to None or 0 would act just like a ListView anyway.

The pagination for the ListView is optional. Only when paginate_by is set to something other than None or 0, will it be paginated.

The other commit was a minor issue when raising a Http404 error, it would return django.utils.functional.lazy.__proxy__ instead of the model's verbose_name_plural when verbose_name_plural isn't specified in the _meta class.