Previously if you created a new grading template chose a date for `Valid from` field and then added a criterion.
The valid from date would reset to null. This would create a validation error on save.
This creates unnecessary confusion for the user.
Now when you have chosen a date and then choose to add a criterion to the template the date does not reset.
The reason for this was that the AutoSave() added to the field was using the wrong event to trigger the setValidFrom().
Since we use bootstraps date picker we have to trigger on "changeDate" event.
Nico Athanassiadis
d0baa11d3b