Adjust env for root vs src

node relevant at the root, but not in src. Broser relevant in src, but not in root.

.eslintrc.js

+module.exports = {
+    env: {
+        node: true
+    }
+};

src/.eslintrc.js

 module.exports = {
+    env: {
+        node: false,
+        browser: true
+    },
     extends: ['scratch/es6', 'scratch/react']
 };