Added a hidden preference to MGLMapView that enables “unnatural zooming”, in which the scroll wheel zooms in and out, as in a Web browser, instead of scrolling the map, as is the platform convention on iOS and OS X. Added a checkbox to osxapp’ preferences window that toggles this hidden preference via a binding. You can either use this checkbox or set the MGLScrollWheelZoomsMapView user default to YES. Fixes #4670.