[dd] Prevent default on gesturemovestart after movement has started.

gesturemovestart is actually triggered on gesturestart/mousedown rather
than on the start of movement. It then throttles down based on a mintime or
min movement. We therefore need to move the preventDefault down to the
function it throttles otherwise we prevent on mousedown of non-dragged
object too.

src/dd/js/drag-gestures.js

@@ -23,8 +23,7 @@
 
         node.on(Y.DD.Drag.START_EVENT, Y.bind(this._handleMouseDownEvent, this), {
             minDistance: this.get('clickPixelThresh'),
-            minTime: this.get('clickTimeThresh'),
-            preventDefault: true
+            minTime: this.get('clickTimeThresh')
         });
 
         node.on('gesturemoveend', Y.bind(this._handleMouseUp, this), { standAlone: true });

src/dd/js/drag.js

@@ -756,6 +756,7 @@
         * @param {EventFacade} ev  The Event
         */
         _handleMouseDownEvent: function(ev) {
+            ev.preventDefault();
             this.fire(EV_MOUSE_DOWN, { ev: ev });
         },
         /**