crypto/cipher: clarify what will happen if len(src) != len(dst) for the Stream interface. (https://golang.org/cl/1754)
crypto/tls: change default minimum version to TLS 1.0. (https://golang.org/cl/1791)
encoding/base64: add unpadded encodings (https://golang.org/cl/1511)
net/http: support for setting trailers from a server Handler (https://golang.org/cl/2157)
net/smtp: add TLSConnectionState accessor (https://golang.org/cl/2151)