Improved compatibility with iOS versions < 7.0 & Demo app.

Hello,

On iOS versions < 7.0 the newly introduced statusBarBackgroundView would 'steal' most touch events destined for the navigation bar buttons, making them almost unusable.

I've also added a version check to the Demo app, because on iOS versions < 7.0 the statusBarBackgroundView would hide part of the navigation bar.

Thanks,
Christos