moment/moment — pull request #1243 by ichernev (2013-10-31 18:32:56+00:00)
Title: Fixed cloning a modified duration

Storing the _input for creating a duration doesn't work for cloning when the
original duration is modified, because input no longer corresponds to the new
duration. Instead use the ms, days and month values which uniquely identify
a duration.

This also happens to fix #1242