L10n updates for: it

L10n updates for: it
From translation svn Revision: 20196

Authors:
Simone Dal Maso <simone.dalmaso@gmail.com>
Alberto Buffolino <a.buffolino@gmail.com>

Stats:
4475	4400	source/locale/it/LC_MESSAGES/nvda.po
6	3	source/locale/it/symbols.dic
36	15	user_docs/it/userGuide.t2t
 3 files changed, 4517 insertions(+), 4418 deletions(-)