fixed getCamera in CameraManager to work correctly; forEach()-construct can't return values

(https://hacks.mozilla.org/2015/04/es6-in-depth-iterators-and-the-for-of-loop/)

Author: bigbozo

src/cameras/2d/CameraManager.js

@@ -308,13 +308,13 @@ var CameraManager = new Class({
      */
     getCamera: function (name)
     {
-        this.cameras.forEach(function (camera)
+        for (var camera of this.cameras)
         {
             if (camera.name === name)
             {
                 return camera;
             }
-        });
+        }
 
         return null;
     },