/* Copyright 1995, Columbia University, all rights reserved.
 * Permission is granted to utilize and disseminate this code or
 *  document without charge, provided that (1) this copyright notice is 
 *  not removed, and (2) all changes made by other than members of the 
 *  MacroModel Development Group at Columbia University are, if further 
 *  disseminated, (a) noted as such; for example, by means of source-code 
 *  comment lines, and (b) communicated back to the author for possible 
 *  inclusion in subsequent versions. */