TimeAgoPipe updates it's output only when it detects it's input has changed.
To do so, it does extract and compare a timestamp (milliseconds).
The output, however, depends not only on milliseconds, but also on locale. That was not taken into account.

I hereby propose a pull request that fixes this.
Locale setting for current moment instance is now considered. If you change locale globally (moment.locale(...)) you will need to make sure new moment instance will trigger the pipe. I consider this the most predictable behaviour.

Please let me know your view, or suggest further changes. Thank you!

Resolves #172.