Animate Popover alpha on device rotation so rotation isn't as harsh. Mimic's Apple's approach to handing rotation animation. 

Removed the guard that caused the popover to get "stuck" in the wrong position when rotating very quickly. This occurred because two didChangeStatusBarOrientation events would fire and then two didChangeDeviceOrientation events instead of interweaving them.

Animate the popover's alpha in and out on rotation so the animation isn't as harsh.