Removed some references to `vis` namespace

lib/timeline/Range.js

@@ -466,8 +466,8 @@ Range.prototype._pointerToDate = function (pointer) {
  */
 function getPointer (touch, element) {
   return {
-    x: touch.pageX - vis.util.getAbsoluteLeft(element),
-    y: touch.pageY - vis.util.getAbsoluteTop(element)
+    x: touch.pageX - util.getAbsoluteLeft(element),
+    y: touch.pageY - util.getAbsoluteTop(element)
   };
 }
 

lib/timeline/component/ItemSet.js

@@ -1211,7 +1211,7 @@ ItemSet.prototype._onAddItem = function (event) {
   }
   else {
     // add item
-    var xAbs = vis.util.getAbsoluteLeft(this.dom.frame);
+    var xAbs = util.getAbsoluteLeft(this.dom.frame);
     var x = event.gesture.center.pageX - xAbs;
     var start = this.body.util.toTime(x);
     var newItem = {