update perseus to 1.3.1
update perseus to 1.3.1

indirectlylit/kolibri,learningequality/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,learningequality/kolibri,mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,learningequality/kolibri,mrpau/kolibri,learningequality/kolibri