Use moment.js for date formatting

Add moment.js ( http://momentjs.com/ ) as a ResourceLoader module
and use it to parse and format date strings. Moment.js seems to be
the least bad option right now; eventually it should be replaced
by i18n functionality in core Javascript modules.

Change-Id: I332655778be3d694781b83fa5dea1e59770d8866
Merge "Use moment.js for date formatting"