Use let when appropriate

README.md

 # acos-webdev-iwdap
 
 Content package for Acos-servers that adds web development exercises
-designed for *Introduction to Web Development and Programming*.
+where student experiments with web using a browser inspector tool.
 
 ## Installation
 
-For the time being, this package requires that `acos-webdev` package has been installed manually.
+This package requires that `acos-webdev` package has been installed
+as a dependency.
 
 ## Testing
 
-Tests are written with WebDriverIO, refer to the `acos-server` documentation on testing.
+Tests are written with WebDriverIO, refer to the `acos-server`
+documentation on testing.

index.js

 /* global module, require, __dirname, console */
 /* jshint globalstrict: true */
 'use strict';
-var nj = require('nunjucks');
-var fs = require('fs');
+let nj = require('nunjucks');
+let fs = require('fs');
 
-var AcosMod = function () {};
+let AcosMod = function () {};
 
-var baseDir = __dirname;
-var content = JSON.parse(fs.readFileSync(baseDir + '/content.json', 'utf8'));
+let baseDir = __dirname;
+let content = JSON.parse(fs.readFileSync(baseDir + '/content.json', 'utf8'));
 
 AcosMod.initialize = function (req, params, handlers, cb) {
-  var templateDir = baseDir + '/templates/';
+  let templateDir = baseDir + '/templates/';
   nj.configure(templateDir, { autoescape: false });
-  var config = content[params.name];
+
+  let config = content[params.name];
   config.abFlag = params.abFlag;
+
   if (config.template) {
     config.html = nj.render(config.template, config);
   }
-  var templateParam = {
+
+  let templateParam = {
     id: 'acos-webdev-inspector-' + params.name,
     config: JSON.stringify(config),
     acceptTest: config.acceptTest,