0.007 29/8/2019
  Add clone method
0.006 13/6/2019
  Add Test::More and Test::Exception as dependencies.
  Handle negative numbers properly in peek function.
0.005 6/06/2019
  improvements to peek method and tests.
0.004 9/05/2019
  add peek, current_and_next/previous, and size methods
0.003 11/02/2019
  Fix github issue #1 ->next($num) and ->prev($num) broken.