CKViewController : Fixes an issue introduces after iOS7 support where setting the right or left button with a barButtonItem who's style was not applied, resulted in a non styled button.
Setting left and right bar button item is now non animated. Methods have been added to set tees button animated.
UIViewController : adds topMostPresentedViewController method that gets the top most presented view controller by iterating on the hierarchy.
This is used when presenting blur modal view controller so that it has not to be managed at the application level.
Improves UIImage imageThatFits:crop method.