Refactor key parsing, marshaling, and serialization to be a bit more flexible R=agl, dave, djm CC=golang-dev https://golang.org/cl/5650067
R=golang-dev, dave, agl CC=golang-dev https://golang.org/cl/5577070
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