Localization/Internationalization support!

Written for MineSweeper by Valerio Bozzolan on 2014-07-15

Now the app is multilanguage, starting with
* de - Deutsch
* en - English
* it - Italiano
* zh - 中国的

To add languages, see the /README.txt file.

Thanks to marcelklehr & fabi1cazenave for their work on the Localization script in Javascript.