The album_db should really be controlled from within the Album tag, so
this patch adds functions to find or create Album tags to the tags
namespace.
Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>
Also make it inherit from the GenericTag base class. Also also, add a
unit test specific to Album tags. Finally, I remove the corresponding
section of the DESIGN file since it is no longer needed.
Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>