Made photosets responsive

I've used the Tumblr-provided but mysteriously undocumented {Photoset} tag to render photosets at 100% of parent width, and a few lines of JavaScript to make mobile browsers pay attention...

For reasons unbeknownst to me, Safari & Chrome (on iOS 6 & 7) would otherwise display the photoset iframe at it's maximum possible width, and not 100% of the viewport's.

The JS I wrote to do this is probably not flawless, but I figured it was better than including 30kb+ library to do it. 

Tested, working in iOS 7 Chrome & Safari. Test Tumblelog: http://ea-photosets-ashley.tumblr.com