internal/catmsg: added varint implementation

the catmsg package contains functionality local to
x/text internal related to the catalog package.

Change-Id: Iba503cf7dd67ad82973727bc096e4732d4dcf56b
Reviewed-on: https://go-review.googlesource.com/41330
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
2 files changed