[RCD] updated italian (it_IT) translation

hello,

in attach the updated italian (it_IT) translations file from roundcube (created with the online http://translator.roundcube.net/ tool);

I also 'attach' many thanks all the developers for the great software and the outstanding speed in patching and adding new features!

PS in order to send this e-mail to the dev mlist (as suggested on the online translator tool) I had to subscribe to the list, otherwise it bounced me the mail back with this error:

Recipient address rejected: Please wait 5 minutes after you subscribe to dev@lists.roundcube.net before attempting to post; or subscribe/resubscribe at http://lists.roundcube.net