fix(url): allow hierarchical facets in trackedParameters

+ fix by upgrading the helper, see
algolia/algoliasearch-helper-js#295

Author: vvo

npm-shrinkwrap.json

@@ -30,6 +30,7 @@
   },
   "repository": "algolia/instantsearch.js",
   "devDependencies": {
+    "algoliasearch-helper": "^2.9.1",
     "autoprefixer": "^6.3.1",
     "babel-cli": "^6.6.0",
     "babel-core": "^6.6.0",