Clean up the binding of show_textbooks and show_other_quarters no longer needed in static/js/course_list.js.
Clean up the binding of show_textbooks and show_other_quarters no longer needed in static/js/course_list.js.

uw-it-aca/myuw,fanglinfang/myuw,uw-it-aca/myuw,uw-it-aca/myuw,fanglinfang/myuw,fanglinfang/myuw,uw-it-aca/myuw