How to tell the version number of RxJS
<p>How to tell the version of the installed RxJS from the code? For example:</p>

<pre><code>var Rx = require('rxjs/Rx');
console.log(Rx.rev);   // undefined
console.log(Rx.version);  // undefined
</code></pre>

<p>Second question: How to tell if it's rxjs5 ?</p>