go1.5.txt: log: add global Output function

Change-Id: I5a54a041cfe9ff2d9514f2d6596b53ec7fc91845
Reviewed-on: https://go-review.googlesource.com/2689Reviewed-by: Rob Pike <r@golang.org>

doc/go1.5.txt

@@ -4,6 +4,7 @@ bufio: add Reader.Discard (https://golang.org/cl/2260)
 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)
+log: add global Output function (https://golang.org/cl/2686)
 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)