docs(readme): improve readme

README.md

@@ -1,15 +1,14 @@
-yii2-plupload
-=============
-The plupload extension for the Yii2 framework
+# yii2-plupload
 
-Installation
-------------
+A [plupload](http://www.plupload.com/) extension for the Yii2 framework
+
+## Installation
 
 The preferred way to install this extension is through [composer](http://getcomposer.org/download/).
 
 Either run
 
-```
+```sh
 php composer.phar require --prefer-dist boundstate/yii2-plupload "*"
 ```
 
@@ -22,10 +21,10 @@ or add
 to the require section of your `composer.json` file.
 
 
-Usage
------
+## Usage
 
-Once the extension is installed, simply use it in your code by  :
+Once the extension is installed, simply create an upload button with:
 
 ```php
-<?= \boundstate\plupload\Plupload::widget(); ?>```
+<?= \boundstate\plupload\Plupload::widget(); ?>
+```