3D media flag support

Hi,

I've seen 3D flag support in Confluence Customizable Mod, and really liked it. This branch incorporated a 3D flag in the various media views for movies.
The flag will appear in any view that displays the "HD" flag. Most of the time it's next to it, in "Media Info 3" it's above the "HD" flag.

I didn't implement this for episodes - just assuming there's not much 3D tv shows out there... can be added, of course.

This flag is based on filename matching, since as of now there's no inherent support for fetching 3D info from XBMC. The filename has to have either "3dbd" or "SBS" in it for the flag to appear.

Here's a gallery displaying the new flag: http://imgur.com/a/naupN#0