Add link to instructions of PHP install

Author: miripiruni

README.md

@@ -7,6 +7,13 @@ The algorithm of CSScomb simulates web-technologists actions upon working with C
 
 For more info, online demo and tests see [csscomb.com](http://csscomb.com/)
 
+
+The Requirements
+------------
+
+* [PHP](http://windows.php.net/download/) ([Make sure](https://github.com/miripiruni/CSScomb/tree/master/src/plugins/csscomb.notepad_plus_plus#required) that the path to the PHP is in an environment variable)
+
+
 ## Installation
 
 ### With Pathogen