Respect recognizesPanGesture property

Respect recognizesPanGesture property even if a UIPanGestureRecognizer has been added.

This allows us to dynamically alter wether to recognise pan gestures or not.

Specifically, I sometimes have childviewcontroller with another childviewcontroller that I display as an overlay. In this case, I want the user to make a choice in my overlayed viewcontroller, and disable panning. Once the overlayed viewcontroller is removed, panning is re-enabled.