Include migrations in pip package
Use absolute paths in gitignore
Allow editing of mentoring XML content from Studio
Add XML editor, with default sample content, to Studio editing view
Add CodeMirror XML editor to Studio view & XML validation
Rename `<quizz>` into `<mcq>` for consistency with upcoming `<mrq>`

Also preserve `<quizz>` binding for compatibility. Split quizz/MCQ
blocks into individual python files
Factor out part of MCQBlock into QuestionnaireAbstractBlock
Allow tips to process multiple submissions for accepting/displaying
Add base support for MRQ, with tips displayed next to the answers
MRQ: Add skinning of feedback popups next to each response
Remove 'Not completed' status indicator when not completed yet
MRQ: Adding sample MRQ to default mentoring content
Cleanup duplicate class name in MCQ/MRQ DOM structure & CSS
MRQ: Update skinning of individual item tip from feedback
Data export: Only export answers from the current course
Merge branch 'master' into freetext-mrq
MRQ: Add message popup to MRQ, upon any click on submit
Rename "submit" button to "Check"
Remove title from MRQ individual feedback
Revert the "Check" button to "Submit"