Fixed issue with reversed scrolling direction when mouse wheel is used.

Fixed the issue (cosmocode#208) with
a reversed (up <-> down) scrolling direction when the mouse wheel is used.
This is done by backporting the change:
  handsontable/handsontable@378ab1f
in the bundled "handsontable" JavaScript library from version 0.38.0 to
version 0.34.1 which is bundled with the edittable plugin.

lib/handsontable.full.js

@@ -48545,13 +48545,15 @@ function TableView(instance) {
 
   if (!(0, _browser.isChrome)() && !(0, _browser.isSafari)()) {
     this.eventManager.addEventListener(instance.rootElement, 'wheel', function (event) {
-      event.preventDefault();
-
       var lineHeight = parseInt((0, _element.getComputedStyle)(document.body)['font-size'], 10);
       var holder = that.wt.wtOverlays.scrollableElement;
 
-      var deltaY = event.wheelDeltaY || event.deltaY;
-      var deltaX = event.wheelDeltaX || event.deltaX;
+      if (holder !== window) {
+        event.preventDefault();
+      }
+
+      let deltaY = (-1) * event.wheelDeltaY || event.deltaY;
+      let deltaX = (-1) * event.wheelDeltaX || event.deltaX;
 
       switch (event.deltaMode) {
         case 0: