Merge pull request #35 from tobybrad/master

Add section on XMLHttpRequest for Node to README

Author: billba

README.md

@@ -40,6 +40,17 @@ There are several ways:
 2. Use the unpkg CDN, e.g. `<script src="http://unpkg.com/botframework-directlinejs/directLine.js"/>`
 3. `npm install botframework-directlinejs`
 
+## Using from within a Node environment
+
+This library uses RxJs/AjaxObserverable which is meant for use in a DOM environment. That doesn't mean you can't also use it from Node though, you just need to do a couple of extra things:
+
+1. `npm install --save xhr2`
+2. Add the following towards the top of your main application file:
+
+```typescript
+global.XMLHttpRequest = require("xhr2");
+```
+    
 ## How to create and use a directLine object
 
 ### Obtain security credentials for your bot: