Deeper moment duration support

[connormlewis]

I would like to have more control over how this directive formats durations. This is not something that is supported directly by the momentjs library, but there is another project called moment-duration-format that allows the duration objects to be formatted very precisely. It can be found here: https://github.com/jsmreese/moment-duration-format.

Is this something you would be interested in having support for?