code: public static String getName(String datatypeKey)
      {
      	Datatype datatype = getDatatype(datatypeKey);
      	return datatype.getName();
      }
docs: Retrieves the preferred name of a data type.
  
  @param datatypeKey URI (URL or URN), ID, or nickname of a data type
  @return the common name of the data type
  
  @throws IllegalArgumentException when not found