Rewrite performed with this command:
sed -i '' 's_code.google.com/p/go\._golang.org/x/_g' \
$(grep -lr 'code.google.com/p/go.' *)
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/170920043
e.g. chmod +w, checkout.
Also: add a TIPS section to the documentation.
LGTM=crawshaw
R=crawshaw, gri
CC=golang-codereviews
https://golang.org/cl/136780044