OpenSocial QA for Dev Guide

Filed two bugs dealing with Google's updated v3 API. Gadgets using the v2 API cannot be placed on a Liferay page. Also, another note that was added and is a pretty major change: **Google's PubSub has been deprecated**.

https://issues.liferay.com/browse/LRDOCS-811
https://issues.liferay.com/browse/LRDOCS-812