Try to test with nyc

Author: sergeysova

package.json

@@ -7,7 +7,7 @@
     "dev": "nodemon -w lib -w examples -x \"npm run build && node examples/test.js\"",
     "clean": "rimraf ./dist ./docs",
     "build": "babel -d ./dist ./lib",
-    "test": "NODE_ENV=test ava",
+    "test": "NODE_ENV=test nyc ava",
     "coverage": "NODE_ENV=test nyc report --reporter=text-lcov",
     "lint": "eslint ./lib",
     "docs": "documentation build -f html -o docs",