Added support for skin.widgets addon

I've added skin.widgets support to your skin. With this commit not only recent items can be displayed on the home page, but also recommended items (e.g. the next unwatched episode  of a serie you are following) and/or random items. 

Three extra buttons in the skin-settings allow you to set 'recent', 'recommended', or 'random' for respectively Movies, TV, and Music. The skin.widgets addon can be found in the original xbmc-repo under services.

Known bugs: 
1. Only works after skin-settings at least opened once. XBMC needs to write the initial settings to guisettings.xml, which I now do when skin-settings is opened. Not sure if there is a better place to initialize these settings.
2. Recommended items does not always give 9 items. If the number of items is less than 9, it just leaves these tiles empty, however the black overlay still is running.