Builds context with various required variables.

def construct_context(self, request):
        """
        Builds context with various required variables.
        """
        opts = self.model._meta
        app_label = opts.app_label
        object_name = opts.object_name.lower()
        form = self.construct_form(request)

        media = self.media(form)
        context = {
            'user': request.user,
            'title': '%s %s' % (self.label, opts.verbose_name_plural.lower()),
            'tool': self,
            'opts': opts,
            'app_label': app_label,
            'media': media,
            'form': form,
            'changelist_url': reverse('admin:%s_%s_changelist' % (
                app_label, object_name
            ))
        }

        # Pass along fieldset if sepcififed.
        if hasattr(form, 'fieldsets'):
            admin_form = helpers.AdminForm(form, form.fieldsets, {})
            context['adminform'] = admin_form

        return context