Updated Developer Guide (markdown)

Developer-Guide.md

@@ -45,6 +45,7 @@ The minimum requirements are:
 * Git
 * Python 2.6 or 2.7 with a couple of extra modules (see below)
 * Java 7 (JRE and JDK)
+* [Node.js](http://nodejs.org/) 
 * [PhantomJS](http://phantomjs.org/) 1.6 or higher
 
 The executables `git`, `java`, `jar`, `python`, and `phantomjs` should be in your `PATH`.
@@ -58,6 +59,10 @@ or
 
 depending on your OS and Python installation.
 
+To install the Node.js dependences run
+
+    $ npm install
+
 Optionally, you can also install JSDoc 3. Installing JSDoc 3 is necessary
 if you want to run the full integration suite.