New: Add "Audit" feature.

htdocs/admin/tools/listevents.php

htdocs/admin/tools/pre.inc.php

htdocs/comm/prospect/prospects.php

htdocs/core/events.class.php

htdocs/includes/menus/barre_left/eldy_backoffice.php

htdocs/includes/menus/barre_left/eldy_frontoffice.php

htdocs/langs/en_US/admin.lang

htdocs/langs/fr_FR/admin.lang

mysql/migration/2.2.0-2.4.0.sql

mysql/tables/llx_events.sql