misc
Remove quiz_question_feedback().
Fix wrong quiz loading function.
Move details of quiz_end_scoring() to FormSubmission class.
Move details of quiz_end_actions() to FormSubmission class.
Remove quiz.take.inc
Move quiz_jumper_form() to quiz.pages.inc
Remove quiz_get_quiz_options().
Avoid using $quiz name, lead to misunderstanding.
Remove legacy code in quiz_add_question_to_quiz().
Rename _quiz_get_question_types() => quiz_get_question_types().
Move quiz_get_question_types() to quiz_question.module.
Move quiz_question_feedback_access() to quiz.hooks.inc
Remove quiz_feedback_can_review().
Remove _quiz_add_revision_checkbox().
misc
Find 'quiz node', replace with 'quiz entity'.
Clean up quiz.api.php
Move assets files under ./misc
question_bg.png is not being used, remove it.