Tiny date, time diff calculator

 pdd (python3 date diff) is a small cmdline utility to calculate date and
 time difference. If no program arguments are specified it shows the current
 date, time and timezone.
 .
 Feature
 .
  - calculate date difference
  - calculate time difference
  - calculate diff from today and now
  - add, subtract duration (timeslice) to/from date (time)
  - show current date, time and timezone
  - minimal dependencies