added documentation for using Web Font Loader as CommonJS module

Author: Prinzhorn

README.md

@@ -44,7 +44,7 @@ It is also possible to use the Web Font Loader asynchronously. For example, to l
    WebFontConfig = {
       typekit: { id: 'xxxxxx' }
    };
-   
+
    (function(d) {
       var wf = d.createElement('script'), s = d.scripts[0];
       wf.src = 'https://ajax.googleapis.com/ajax/libs/webfont/1.5.18/webfont.js';
@@ -57,6 +57,18 @@ Using the Web Font Loader asynchronously avoids blocking your page while loading
 
 The FOUT can be more easily avoided when loading the Web Font Loader synchronously, as it will automatically set the `wf-loading` class on the HTML element as soon as `Webfont.load` has been called. The browser will wait for the script to load before continuing to load the rest of the content, FOUT is avoided.
 
+Web Font Loader is also available on npm as a CommonJS module. Just `npm install webfontloader` and then require it in your code.
+
+```js
+  var WebFont = require('webfontloader');
+
+  WebFont.load({
+    google: {
+      families: ['Droid Sans', 'Droid Serif']
+    }
+  });
+```
+
 ## Configuration
 
 The Web Font Loader configuration is defined by a global variable named `WebFontConfig`, or passed directly to the `WebFont.load` method. It defines which fonts to load from each web font provider and gives you the option to specify callbacks for certain events. When using the asynchronous approach, you must define the global variable `WebFontConfig` before the code that loads the Web Font Loader (as in the example above).