Split the profile parsing code out of cmd/cover into
a reusable package, to support third-party coverage
tools.
R=golang-dev, r, adg
CC=golang-dev
https://golang.org/cl/36050045
Present the files in lexical order so the output is reproducible
and easier to navigate. Do a little type rearrangement to simplify
things while we're there.
R=adg
CC=golang-dev
https://golang.org/cl/14357043