Add an option to only allow edge pan gesture?

In my app, users can already swipe to the left with two fingers to use some functionality. This conflicts with the slide menu's `rightPanGesture`. Sure I can set `maximumNumberOfTouches` to 1 so swiping with 1 finger opens the menu and swiping with 2 fingers does the other thing but the user might get confused by this 1 finger 2 fingers thingy. So I just want to use an `UIEdgePanGestureRecognizer` to open the slide menu. Is there a way to do that other than adding a recognizer manually and calling `openRight`?

Start by tracing the existing `rightPanGesture` handling and how it invokes `openRight`; compare that path with the requested `UIEdgePanGestureRecognizer` behavior. Done means the slide menu can be configured to open from an edge pan without conflicting with the app’s two-finger swipe, while preserving the existing gesture option.

Written by the indexing model from the issue text.