fix(ngTouch): add $event to ng-swipe

Existing documentation implies that an Event object should be available
as `$event` on swipe directives, which previously was only working for
`ng-click`.

Closes #4071
Closes #4321

test/ngTouch/directive/ngSwipeSpec.js

@@ -66,6 +66,23 @@ var swipeTests = function(description, restrictBrowsers, startEvent, moveEvent,
       expect($rootScope.swiped).toBe(true);
     }));
 
+    it('should pass event object', inject(function($rootScope, $compile) {
+      element = $compile('<div ng-swipe-left="event = $event"></div>')($rootScope);
+      $rootScope.$digest();
+
+      browserTrigger(element, startEvent, {
+        keys : [],
+        x : 100,
+        y : 20
+      });
+      browserTrigger(element, endEvent,{
+        keys: [],
+        x: 20,
+        y: 20
+      });
+      expect($rootScope.event).toBeDefined();
+    }));
+
     it('should not swipe if you move too far vertically', inject(function($rootScope, $compile, $rootElement) {
       element = $compile('<div ng-swipe-left="swiped = true"></div>')($rootScope);
       $rootElement.append(element);