This allows us to drop some crufty scripting and provides a firmer
footing for building better tools for preparing documents with source
code inside.
Also eliminate line numbers from the examples and text.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4650069
This aligns the naming scheme with the testing package and
also lets govet work on more logging calls.
R=rsc
CC=golang-dev
https://golang.org/cl/4001048