fix global grade calculation with wrong passing grade when not using percentage grading system
can create a teacher directly from the teachers assignments screen
import subjects from previous batches: can filter and order
migration: re-compute all final grades of students in case we have evaluations, to apply the fix of version 0.1.5
upgrade version number from 0.1.5 to 0.1.6
fix test a version before to install it definitively
Merge branch 'master' of https://github.com/passerellesnumeriques/Students-Database into dev

Conflicts:
	www/version
Merge branch 'dev' of https://github.com/passerellesnumeriques/Students-Database into dev_travel