Added using static and aliases (#126)

Author: bkoelman

Src/Guidelines/2400_LayoutGuidelines.md

@@ -62,7 +62,7 @@ NOTE: Requires Markdown Extra. See http://michelf.ca/projects/php-markdown/extra
 
 	// Microsoft namespaces are first
 	using System;
-	using System.Collections;
+	using System.Collections.Generic;
 	using System.XML;
 
 	// Then any other namespaces in alphabetic order
@@ -71,7 +71,8 @@ NOTE: Requires Markdown Extra. See http://michelf.ca/projects/php-markdown/extra
 	using Telerik.WebControls;
 	using Telerik.Ajax;
 
-Always place using directives at the top of the file, before any namespace declarations (not inside them).
+Using static directives and using alias directives should be written below regular using directives.
+Always place these directives at the top of the file, before any namespace declarations (not inside them).
 
 ### <a name="av2406"></a> Place members in a well-defined order  (AV2406) ![](images/1.png)
 Maintaining a common order allows other team members to find their way in your code more easily. In general, a source file should be readable from top to bottom, as if reading a book, to prevent readers from having to browse up and down through the code file.