Rotation behavior on iOS6+ & CenterViewController gesture recognizers

Hi,

1. 
I saw that the 3 methods used in iOS6 where not passed to the centerViewController so I did it.

So if a centerViewController is here we check if it is a UINavigationController (due to an iOS6 bug) and if it is we directly go to the visible UIViewController. If it's not an UINavigationController we get the value from centerViewController.

EDIT : 
2. after changing the CenterViewController I updated the gesture recognizers

PS : you did a very good job for the SideMenu :)