Fix viewport for iPhone 5

On my iPhone, when I saved the app to the home screen and opened it, it looked like this:
![ios simulator screen shot jul 15 2013 11 52 26 am](https://f.cloud.github.com/assets/173440/799992/3b07d338-ed80-11e2-8a3e-94e4f7beaaa9.png)
Notice the two ugly black bars? I did too.

With this change, it looks like this:
![ios simulator screen shot jul 15 2013 11 52 56 am](https://f.cloud.github.com/assets/173440/799995/4758327c-ed80-11e2-8fbd-83d94065482e.png)

Yay! I used [this technique](http://stackoverflow.com/a/13769323) to fix the bug.