Select
iOS port of the JVM/Android SelectDragDetector. Mirrors the JVM pattern: pick is driven synchronously on DOWN (via WorldWindow.pick which drains the pick frame inline), so by the time we return to the dispatcher we already know whether a draggable renderable is under the finger. Subsequent MOVE events drive the drag directly when armed; otherwise they fall through to earth.worldwind.BasicWorldWindowController for camera panning.