add 'order' field to contributions and add migrations
sort contributions in course_forms for staff and contributors and in student_vote
fix test
change tolerance for sortable
prevent "add another" from moving
enable automatic checking/unchecking of responsible and edit checkboxes also for newly added table rows
prevent deleting responsible contributor
refactor student/views.py::vote. make the ordering of contributors explicit.
make the results respect the contribution ordering
make the tests work with enabled debug toolbar
Merge pull request #413 from janno42/order_contributors

Order contributors
fix KeyError in message when fully reviewing course
add reward point models and a reward point redemption page for students
automatically grant reward points to students when they finished voting for their last course in a semester
added reward points overview per semester for staff
adding pages for editing reward point redemption events
added texts on rewards page and enabled translations
added creating and deleting events; added date picker to form fields
added excel export for reward point redemption events
added infobox text about reward points