Update front page categories to match XBMC

Show the same Add-on categories as inside the XBMC Add-on browser. Use the type not the name to browse from now on. More info here

http://forum.xbmc.org/showthread.php?tid=156157&pid=1559676#pid1559676

- Creates new database fields for Add-on type and provider
- Updates main page to show new categories
- Filters the browse page to use the new categories
- Extra filter for xbmc.python.pluginsource since it uses a silly 2nd field for video/audio/image add-ons

![image1](https://f.cloud.github.com/assets/1050512/1623685/fad6e678-56b6-11e3-8024-ddfe87c89112.png)