Changed all uses of bytes.Add (aside from those testing bytes.Add) to append(a, b...).
Also ran "gofmt -s" and made use of copy([]byte, string) in the fasta benchmark.
R=golang-dev, r, r2
CC=golang-dev
https://golang.org/cl/3302042
This is the first of probably four separate CLs
for the new implementation of the json package.
The scanner is the core of the new implementation.
The other CLs would be the new decoder,
the new encoder, and support for JSON streams.
R=r
CC=golang-dev
https://golang.org/cl/802051
