removed async, uneeded

Author: jishi

package.json

@@ -11,7 +11,6 @@
     "url": "https://github.com/jishi/node-sonos-http-api.git"
   },
   "dependencies": {
-    "async": "~1.5.0",
     "basic-auth": "~1.0.3",
     "fuse.js": "^2.2.0",
     "node-static": "~0.7.0",