Duration>>#milliseconds changed to be portable
          Reason for change
          Other Smalltalk platforms answer just the millisecond portion of a Duration for the #milliseconds message. 
          Change
          The implementation of Duration is changed to enhance cross-platform portability:
          •	the #milliseconds method is changed to answer just the millisecond portion of a Duration.
          •	the #asMilliseconds message is added to answer the value of a Duration expressed in milliseconds (the old behavior of #milliseconds).
          Action required
          Change:
  aDuration milliseconds
to:
 aDuration asMilliseconds
         
        
          Last modified date: 07/02/2019