Add generic view mixins for Django 1.3

[bradleyayers]

I'm thinking a SingleTableMixin and MultipleTableMixin would be good. The following is a quick attempt at a SingleTableMixin, feedback would be appreciated. I think implementing the ability to change querystring variable names first (issue #5) would be a good idea, and necessary for MultipleTableMixin anyway.

class SingleTableMixin(object):
    """
    Adds a suitable table to the context. Requires a ``table`` attribute on the
    view.
    """
    table = None
    context_table_name = "table"

    def get_context_data(self, **kwargs):
        table = self.table(self.get_queryset(), order_by=self.request.GET.get('sort'))
        table.paginate(page=self.request.GET.get('page', 1))
        context = super(TableMixin, self).get_context_data(**kwargs)
        context[self.context_table_name] = table
        return context

[bradleyayers]

I'm going to consider this done until a decent pattern is developed for MultipleFooMixin classes.