[x/tour] Add an appEngineMode slide for the NYC talk.
[x/tour] Add an appEngineMode slide for the NYC talk.

R=adg
CC=golang-dev
https://golang.org/cl/6191044
X-Tour-Commit: 94ade8ab8b20abc3c090e1d3fbd44d246dee64c9

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website