Bump advised Node 4 version to >=4.1.1

See nodejs/node#2943 for the discussion about the issue

Refs nodejs/node#2931

Author: mgol

package.json

@@ -44,6 +44,6 @@
     "test": "grunt"
   },
   "engines": {
-    "node": ">=4.1.0"
+    "node": ">=4.1.1"
   }
 }