[Developers] Cleanup of types the /book domain

[Bryan Cheung]

There's some cleanup that affects types in the /book domain.  The  
details can be found on the data-model list:

http://lists.freebase.com/pipermail/data-modeling/2008-March/000462.html

If you have an application that might be affected or have an opinion  
regarding the change, please post comments to that email thread.  You  
can subscribe to the data-model list here:

http://lists.freebase.com/mailman/listinfo/data-modeling

Bryan Cheung