PerformanceControl: updated IT translation

PS2: Missing strings
PS3: Better tranlsation
PS4: Fianl version?

Original Translation by Stefano187
http://forum.xda-developers.com/member.php?u=4643755
Updated on 15 Dec 2013 by ale8530 and L. Luzzi

Change-Id: I3f201bc87df83c711c985a441a85f77cefe5aadf
merge changes from Omni 4.4 into local branch