Pan gesture only works from the navigation bar

[dulacp]

Sometimes for really simple card controllers it can be great to be able to move/slide them from wherever the user want to.

To be able to close the card controller from the whole navigationController.view on not only the navigationController.navigationBar.

I'll add again another configuration option, and make it backward compatible of course.

[KieranLafferty]

Hey, yes currently it only has the pan gesture assigned to the uinavigationbar of the uinavigationcontoller. I was looking to avoid the case where the pan gesture may interecept non intentional pan gestures making the UIViewcontroller unresponsive to other actions (i.e button presses and text input). I will try to find some time to test this pull request out before merging