Use ES6 linting rules in the project root

Update all tests for `no-var` and `prefer-arrow-callback` (using `--fix`)

test/integration/looks.js

@@ -1,35 +1,35 @@
-var path = require('path');
-var test = require('tap').test;
-var attachTestStorage = require('../fixtures/attach-test-storage');
-var extract = require('../fixtures/extract');
-var VirtualMachine = require('../../src/index');
+const path = require('path');
+const test = require('tap').test;
+const attachTestStorage = require('../fixtures/attach-test-storage');
+const extract = require('../fixtures/extract');
+const VirtualMachine = require('../../src/index');
 
-var uri = path.resolve(__dirname, '../fixtures/looks.sb2');
-var project = extract(uri);
+const uri = path.resolve(__dirname, '../fixtures/looks.sb2');
+const project = extract(uri);
 
-test('looks', function (t) {
-    var vm = new VirtualMachine();
+test('looks', t => {
+    const vm = new VirtualMachine();
     attachTestStorage(vm);
 
     // Evaluate playground data and exit
-    vm.on('playgroundData', function (e) {
-        var threads = JSON.parse(e.threads);
+    vm.on('playgroundData', e => {
+        const threads = JSON.parse(e.threads);
         t.ok(threads.length === 0);
         t.end();
         process.nextTick(process.exit);
     });
 
     // Start VM, load project, and run
-    t.doesNotThrow(function () {
+    t.doesNotThrow(() => {
         vm.start();
         vm.clear();
         vm.setCompatibilityMode(false);
         vm.setTurboMode(false);
-        vm.loadProject(project).then(function () {
+        vm.loadProject(project).then(() => {
             vm.greenFlag();
 
             // After two seconds, get playground data and stop
-            setTimeout(function () {
+            setTimeout(() => {
                 vm.getPlaygroundData();
                 vm.stopAll();
             }, 2000);