 allocfet - allocates and initialized an empty fet structure.

 reallocfet - reallocates an fet structure of a
              specified length.
 freefet - deallocates the memory for an fet structure.

 readfetfile - opens an fet file and reads its contents into an
               fet structure.
 updatefet - replaces a feature entry in an fet structure, or creates
             a new entry if the feature does not already exist.
 writefetfile - write the contents of an fet structure to the
                specified file.
