Quiz creation form doesn't respect Rubik theme's two-column layout

When using Rubik as the admin theme, form elements can't be placed in Rubik's sidebar, using the hook Rubik exposes for this (hook_node_form_sidebar()).

This seems to be because Rubik defines its hook in a preprocessor function for theme_node_form(), and Quiz doesn't render its node form through that theme function.

The attached patch adds a line to theme_quiz_node_form() in quiz.admin.inc, line 1586, to pass $form through theme_node_form() and return it. This fixes the issue for me.