Sort categories and series
Correct sum that started one element too late.
(classes_to_join) put uniq and compact at beginning of function, because delete("Student") should be called afterwards
make grade distribution discrete and forgotten add EN and DF to query
Improve update function, so that color assignments stay clear.
Merge branch 'migration'
Add result limitation for animation.
Improve model's limitation algorithm; improve columnchart's variable usage in update algorithm.