Update lang/it_IT.lang

Fixed the following missing translations:
 ! Missing translation for Search / Open URL
 ! Missing translation for Paused
 ! Missing translation for Artists
 ! Missing translation for Indexed mode
 ! Missing translation for Indexing
 ! Missing translation for Add and remove items on homepage
 ! Missing translation for Background
 ! Missing translation for Beta testing passwords
 ! Missing translation for Browsing
 ! Missing translation for Default
 ! Missing translation for Home page
 ! Missing translation for Installed version higher than available
 ! Missing translation for List of albums
 ! Missing translation for Loading screen
 ! Missing translation for Movies
 ! Missing translation for Preferred views from plugins
 ! Missing translation for Screen saver
 ! Missing translation for TV channels
 ! Missing translation for Fonts and user interface styling
 ! Missing translation for Look and feel
 ! Missing translation for Defaults
 ! Missing translation for Fonts
 ! Missing translation for Installed fonts
 ! Missing translation for Reset main font to default
 ! Missing translation for Reset narrow font to default
 ! Missing translation for Reset subtitle font to default