update installation npm section

Author: yyx990803

source/guide/installation.md

@@ -1,7 +1,7 @@
 ---
 title: Installation
 type: guide
-order: 1
+order: 0
 vue_version: 1.0.0-rc.1
 dev_size: "237.15"
 min_size: "71.70"
@@ -30,18 +30,21 @@ Some environments, such as Google Chrome Apps, enforces Content Security Policy
 
 ## NPM
 
+NPM is the recommended installation method when building large scale apps with Vue.js. It pairs nicely with a CommonJS module bundler such as [Webpack](http://webpack.github.io/) or [Browserify](http://browserify.org/). Vue.js also provides accompanying tools for authoring [Single File Components](http://localhost:4000/guide/application.html#Single_File_Components).
+
 ``` bash
+# latest stable
 $ npm install vue
-# for csp-compliant version:
+# latest stable + CSP-compliant
 $ npm install vue@csp
-# for dev build (from GitHub):
+# dev build (directly from GitHub):
 $ npm install vuejs/vue#dev
 ```
 
 ## Bower
 
 ``` bash
-# only stable version is available through Bower
+# latest stable
 $ bower install vue
 ```