fix(RTL): Unfixed .css() call post-jquery

Removing jQuery broke any .css() call that's reading inherited styles.
Updated the normalize/denormalizeScrollLeft calls in gridUtil to use
getStyles().

Fixes #1620

src/js/core/services/ui-grid-util.js

@@ -3,7 +3,12 @@
 var module = angular.module('ui.grid');
 
 function getStyles (elem) {
-  return elem.ownerDocument.defaultView.getComputedStyle(elem, null);
+  var e = elem;
+  if (typeof(e.length) !== 'undefined' && e.length) {
+    e = elem[0];
+  }
+
+  return e.ownerDocument.defaultView.getComputedStyle(e, null);
 }
 
 var rnumnonpx = new RegExp( "^(" + (/[+-]?(?:\d*\.|)\d+(?:[eE][+-]?\d+|)/).source + ")(?!px)[a-z%]+$", "i" ),
@@ -792,8 +797,8 @@ module.service('gridUtil', ['$log', '$window', '$document', '$http', '$templateC
     var browser = s.detectBrowser();
 
     var scrollLeft = element.scrollLeft;
-
-    var dir = angular.element(element).css('direction');
+    
+    var dir = s.getStyles(element)['direction'];
 
     // IE stays normal in RTL
     if (browser === 'ie') {
@@ -842,7 +847,7 @@ module.service('gridUtil', ['$log', '$window', '$document', '$http', '$templateC
 
     var browser = s.detectBrowser();
 
-    var dir = angular.element(element).css('direction');
+    var dir = s.getStyles(element)['direction'];
 
     // IE stays normal in RTL
     if (browser === 'ie') {