E3 extensions update to master (E3, GS, GT)

The changes to E3Experiments, GettingStarted, GuidedTour are
interdependent.

Change-Id: Ic0ed8d1db166ece6a147f30ffc2892007ee34ba9
Merge "E3 extensions update to master (E3, GS, GT)" into wmf/1.21wmf11