This is my first attempt at producing the Italian localization for Review Board.

All the messages generated in the .po file by running contrib/i18n/make-messages.py have been translated; however, some messages in the application are still in English, as they lack the "_(...)" syntax in the original source.

The attached diff contains only the .po file, the .mo one should be generated by running contrib/i18n/make-messages.py.

I compiled the .po file, changed settings_local.py and reviewboard/settings.py and checked the translated messages were displayed.

Some messages in the application are still in English as they lack the "_(...)" syntax in the original source.