Added Demo2.js For User Sets

I've added a demo2.js to potentially show people that they can pull
down personal sets using the flickr api as well. Incase anyone is
interested in making a personal gallery using a flickr backend.
Possibly useful for portfolios.

I've also added a div in the index.html for the gallery description. 

Not sure if you're interested but I was thinking of making a bunch of modules for your gallery to import images from multiple services. Such as Flickr. 

Regards, 
Eric Robinson
eric.z.robinson@gmail.com