Twitter Gadget

Hi Dennis,

We got a recent complaint from a reader/user of the User Guide about the Twitter gadget not working for them unless the links were updated to `https`. I tested the Gadget on Liferay 6.2 EE (user tested on 6.2 CE) and I also ran into this. Therefore, I updated all the links in the `Twitter.xml` to use `https`. Let me know if there is an issue with doing it this way.

I also updated old links still referring to your old repo on *googlecode*.

Thanks!

https://issues.liferay.com/browse/LRDOCS-963