message: use localized number formatting

This change implements default localized number
formattting for base-type arguments.
Tailored formatting, like engineering notation,
is planned through the number package.

Change-Id: I58f9c3b5543b627ab8b705a0b32819fdf317754b
Reviewed-on: https://go-review.googlesource.com/46472
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
6 files changed