doc/go1.3.html: update the state of supported platforms
doc/go1.3.html: update the state of supported platforms

LGTM=r
R=golang-codereviews, aram, 0intro, gobot, r
CC=golang-codereviews
https://codereview.appspot.com/100490044

wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang