timrwood/moment — pull request #863 by frasertweedale (2013-06-24 06:34:53+00:00)
Title: fix durations not being cloned properly

``moment.duration`` does not return an equivalent Duration for all
inputs. Add a test for this and fix the issue by reusing the
Duration's constructor argument.

This is an alternative approach to https://github.com/timrwood/moment/pull/858.