merge develop into highlight pregrade

.gitignore

.gitlab-ci.yml

AUTHORS.md

README.md

client/components/Hero.jsx

client/components/feedback/EditPanel.jsx

client/components/feedback/FeedbackBlock.jsx

client/components/feedback/FeedbackPanel.jsx

client/views/Exam.css

client/views/Exam.jsx

client/views/ExamEditor.jsx

client/views/Grade.jsx

client/views/grade/Grade.css

package.json

requirements-dev.txt

tests/api/test_exams.py

tests/api/test_feedback.py

tests/api/test_mc_option.py

tests/conftest.py

tests/data/checkboxes/scanned_page.jpg