Tab

Much of the tab page code was based on the navigator page code.

The cache system does work for pages contained in the tab page. Is this something worth implementing? If so, how should I go about doing it?

fixes #59 
We should discuss using a UIScreenEdgePanGestureRecognizer for the openGesture (which was previously only added to the navigation bar (so we shouldn't call it a menu bar:)). It would only work on iOS 7, but it would make navigation more natural all in all.