Fixed after latest AudioTag changes. Piped input.

 - Added a new AnyTag enum to contain any type of AudioTag. Since
   AudioTag now uses type parameters, it is no longer object safe,
   meaning it can not be boxed. Adding a AnyTag enum and having it
   implement the AudioTag trait is the workaroud for this.
 - Added the ability to pipe input to the program as long as ayou
   specify the tag type.