closes phaserjs#3520

Phaser.Display.Canvas.CanvasPool.first now returns the available pool item instead of always returning null.

Author: mean-ui-thread

src/display/canvas/CanvasPool.js

@@ -126,13 +126,13 @@ var CanvasPool = function ()
     {
         if (canvasType === undefined) { canvasType = CONST.CANVAS; }
 
-        pool.forEach(function (container)
-        {
+        for (var i = 0, len = pool.length; i < len; i++) {
+            var container = pool[i];
             if (!container.parent && container.type === canvasType)
             {
                 return container;
             }
-        });
+        };
 
         return null;
     };