GETOUTPUT Returns output type of a pipeline

     OUT=GETOUTPUT(PP)
     OUT=GETOUTPUT(W)

 INPUT
    P       pipeline object
    W       trained PRTools mapping

 OUTPUT
    OUT     output type string

 DESCRIPTION
 GETOUTPUT returns the output type for a pipeline or trained mapping.
 Outputs may be:
   'data'        - for example from general feature extractors
   'class similarity'  - similarity to a class
   'class distance'    - distance from a class
   'proto similarity'  - similarity to a prototype
   'proto distance'    - distance from a prototype
   'decision'          - crisp decision
   []            - unknown (for algs that cannot be converted into pipeline)