xbmc/xbmc — pull request #1609 by jmarshallnz (2012-10-13 05:29:22+00:00)
Title: Cleanup video music thumbloaders

1. Splits music/video thumbloaders into their own .cpp/.h.
2. Cleans up some unnecessary members in a couple classes.
3. Removes unnecessary backwards compatibility for artist art fetching - all music is rescanned to fetch art anyway.
4. Adds a cache for album art, so that we hit the db once per album only in the music thumb loader.
5. Adds a cache for tvshow art, so that we hit the db once per episode/season only in the video thumb loader.

Note: Doesn't speed up retrieval of fanart for songs/albums: Reason is, we don't have the artist id here, so need to hit the database anyway for that information. To speed this up, we could consider storing the primary artist id in the song/album tables.