fix student_grades
(cherry picked from commit ac755a34cc8b000e3c2215b9b0bbee59632ce312)
game to learn faces
fix wait for frame
(cherry picked from commit 1efb1eccac650518ad5c8310ca465fccf350a871)
Merge branch 'master' of https://github.com/passerellesnumeriques/Students-Database into dev