Merge: lib/time: introduces ISODate

I will soon need this.

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

Pull-Request: #1005
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>