Updated Italian translation

Change-Id: Idb7fd0758b855c5bb78ac0dc5b1093941a90218f
Reviewed-by: Luigi Toscano <luigi.toscano@tiscali.it>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Bump MODULE_VERSION to 5.3.1

Change-Id: Ic583c26c248a4b2b9048bf030a4e5b0b1a481477
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>