Delete 'ilm_debug/todos_files_iassign.ods'

Synchronizing iAssign Git with the current iAssign stable version (until Moodle 5.0).
Small changes in: ilm_manager.php, lang/*/iassign.php
Bigger changes in: ilm_manager_form.php, lib.php, settings_form.php, settings.php, version.php, backup/moodle2/*.php, ilm_debug/escreva.php, ilm_handlers/java.php
New iLM versions: iassign/ilm/iFractions/, iassign/ilm/iHanoi/, iassign/ilm/iVProg/
New file (was missing): settings_activities.php