IND2NAME  Convert category index to name

     N=IND2NAME(LL,IND)

 INPUT
    LL    SDLIST object
    IND   vector of indices

 OUTPUT
    N     Character array with category names

 DESCRIPTION
 IND2NAME converts category indices to names.  If IND is a vector of
 indices, character array is returned.
 Error is raised, if IND contains index out of bounds (smaller than 1 or
 higher than length(LL).

 SEE ALSO
 NAME2IND, GETNAMES