go-tour: recommend installing weekly (just temporarily)
go-tour: recommend installing weekly (just temporarily)

The playground is now updated to the latest weekly snapshot,
so the tour needs to be updated as well. It's not a great
experience to recommend release when they've just been learning
how to write Go 1 code.

R=golang-dev, r
CC=golang-dev
http://codereview.appspot.com/5701068

karabinaa/go-tour-tr,karabinaa/go-tour-tr