nodejs-server: Added npm start scripts on package.json + update README

Author: pjmolina

modules/swagger-codegen/src/main/resources/nodejs/README.mustache

@@ -8,11 +8,10 @@ This example uses the [expressjs](http://expressjs.com/) framework.  To see how
 [README](https://github.com/swagger-api/swagger-codegen/blob/master/README.md)
 
 ### Running the server
-To run the server, follow these simple steps:
+To run the server, run:
 
 ```
-npm install
-node .
+npm start
 ```
 
 To view the Swagger UI interface:

modules/swagger-codegen/src/main/resources/nodejs/package.mustache

@@ -3,6 +3,10 @@
   "version": "{{appVersion}}",
   "description": "{{{appDescription}}}",
   "main": "index.js",
+  "scripts": {
+	"prestart": "npm install",
+	"start": "node index.js"
+  },  
   "keywords": [
     "swagger"
   ],