chore(package): update ava to version 0.16.0 (#21)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -36,7 +36,7 @@
     "bluebird": "^3.3.5"
   },
   "devDependencies": {
-    "ava": "^0.15.2",
+    "ava": "^0.16.0",
     "babel-cli": "^6.11.4",
     "babel-plugin-add-module-exports": "^0.2.1",
     "babel-preset-es2015": "^6.9.0",