Settings namespaces

Changed it to register a namespace for each addon, that way addons will be able to save on different levels ie. on a char (as it previously were), realm, class, race and global basis. Along with that addons can subscribe to events in the database such as on section reset.
Ooh.. But CallbackHandler is a thirdparty library so I don't see any point in changing the formatting in it, because it will be lost upon updating the library anyway. :/