project lint setting: disallow undeclared var

Author: Anand Thakker

.eslintrc

@@ -29,7 +29,8 @@
     "quotes": [2, "single"],
     "indent": [2, 2],
     "curly": 2,
-    "no-shadow": 0
+    "no-shadow": 0,
+    "no-undef": 2
   },
   "env": {
     "node": true,