Update mime dependency to 1.4.1 to fix regex DoS

Author: rback

package.json

@@ -28,7 +28,7 @@
     "async": "~0.9.0",
     "fetch": "~0.3.6",
     "lodash": "~2.4.1",
-    "mime": "~1.2.11",
+    "mime": "~1.4.1",
     "qs": "~2.1.0",
     "sockjs-client": "^1.0.3"
   },