fix(popover): fix popover position on Internet Explorer

Closes #2861

Author: vjrantal

js/angular/service/popover.js

@@ -93,8 +93,9 @@ function($ionicModal, $ionicPosition, $document, $window) {
     var buttonOffset = $ionicPosition.offset(targetEle);
     var popoverWidth = popoverEle.prop('offsetWidth');
     var popoverHeight = popoverEle.prop('offsetHeight');
-    var bodyWidth = $document[0].body.clientWidth;
-    // clientHeight doesn't work on all platforms for body
+    // Use innerWidth and innerHeight, because clientWidth and clientHeight
+    // doesn't work consistently for body on all platforms
+    var bodyWidth = $window.innerWidth;
     var bodyHeight = $window.innerHeight;
 
     var popoverCSS = {