title: node 0.12.x const in strict mode issue
body: <p>I'm running node v0.12.7, and installed protractor through npm.
  Now I'm trying to run the conf.js using this <a href="https://angular.github.io/protractor/#/tutorial">simple tutorial</a>, and I get the following error when executing the command <code>protractor conf.js</code>:</p>
  
  <pre><code>[launcher] Process exited with error code 1
  C:\Users\ramtin\AppData\Roaming\npm\node_modules\protractor\node_modules\selenium-webdriver\index.js:25
  const builder = require('./builder');
  ^^^^^
  SyntaxError: Use of const in strict mode.
      at exports.runInThisContext (vm.js:73:16)
      at Module._compile (module.js:443:25)
      at Object.Module._extensions..js (module.js:478:10)
      at Module.load (module.js:355:32)
      at Function.Module._load (module.js:310:12)
      at Module.require (module.js:365:17)
      at require (module.js:384:17)
      at Object.&lt;anonymous&gt; (C:\Users\ramtin\AppData\Roaming\npm\node_modules\protractor\built\protractor.js:3:17)
      at Module._compile (module.js:460:26)
      at Object.Module._extensions..js (module.js:478:10)
  </code></pre>
  
  <p>Can't update node due to dependency issues it will produce (I'm working on an already-built project which used node 0.12.17).</p>
  
  <p>Using <code>--harmony</code> flag on protractor doesn't work. Do I need to install a specific version of protractor to be compatible with node 0.12.7? Or should I use <code>babeljs</code> to compile <code>ES6</code> to <code>ES5</code>?</p>
  
  <p>If <code>babeljs</code> is the answer, how would I use it for protractor?</p>