Extracts the cost used to generate a bcrypt hash from the hash itself. R=agl, agl, dchest CC=golang-dev https://golang.org/cl/6810051
Manual edits to README. Moved from main Go repository, deleted Makefiles, ran gofix -r go1rename. Tested with: go test code.google.com/p/go.crypto/... R=golang-dev, bradfitz CC=golang-dev https://golang.org/cl/5564059