anchor.diff:  
   INTERFACE OPERATOR(+)
     MODULE PROCEDURE datetime_plus_timedelta
  +  MODULE PROCEDURE timedelta_plus_datetime
     MODULE PROCEDURE timedelta_plus_timedelta
   ENDINTERFACE
   
  
positive.code: !         FUNCTION strftime
  !         FUNCTION strptime
  !
  ! LAST UPDATE: 2013-05-12
  !
  !======================================================================>
  USE,INTRINSIC :: iso_c_binding
  
negative.code: !
  ! MODULE: datetime
  !
  ! VERSION: 0.1.0
  !
  ! AUTHOR: Milan Curcic
  !         University of Miami
  