encoding/binary: use bytes.Reader in read example
encoding/binary: use bytes.Reader in read example

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/13274043

Committer: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

apparentlymart/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,apparentlymart/golang,tv42/old-go,apparentlymart/golang,tv42/old-go,apparentlymart/golang,tv42/old-go,apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,apparentlymart/golang,tv42/old-go