Sub theme integration with OS

#2349 

Dummy repository with with the branches and the zip files: https://github.com/RoySegall/os-subtheme

![appearance page](https://f.cloud.github.com/assets/1222368/495262/abc73506-bbbb-11e2-9252-d815cc25ed6c.png)
![method-select](https://f.cloud.github.com/assets/1222368/495263/abe6fd50-bbbb-11e2-96bc-6c771ca6d1ec.png)
![zip](https://f.cloud.github.com/assets/1222368/495264/abfb9bb6-bbbb-11e2-9ef2-ce258f438582.png)
![screenshot at 2013-05-13 13 49 20](https://f.cloud.github.com/assets/1222368/495266/b48991ac-bbbb-11e2-8480-c1b79fd48064.png)
![screenshot at 2013-05-13 13 50 00](https://f.cloud.github.com/assets/1222368/495265/b48107ee-bbbb-11e2-8073-569bdca5bc67.png)