Let momentjs handle proper pluralization of relative times. This comes
at the sacrifice of displaying 'minutes' in the conversation list
timestamp rather than 'min'. Note that we don't use moment's fromNow
instance method so as to preserve the rounding logic that matches the
Android client.
// FREEBIE
* Apply the same rounding to in message bubbles and conversation list.
Also make them consistent with Android's relative times. Fixes#682
* Show full timestamps when hovering on relative time
* Compute timestamp update delays more precisely:
Set timestamps to self-update as soon as they are able to change
rather than a fixed time since the last update.
* Refactor for customizable/localizable relative times
* Update timestamp tests
* Log timestamp update intervals to help debug #460
