These are the references that affect current Go users.
I left intact references in older release notes;
we can figure out what to do with them later.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/186140043

Conflicts:
	doc/go1.4.html

Change-Id: I1032686f2b3ac6dacaf8f114b8c35cdf221330ca