Link to a YUI Compressor-based minification tool in README. Close necolas#4

Author: necolas

README.md

@@ -21,6 +21,8 @@ It is suggested that you read through the `normalize.css` file and customise it
 
 If you prefer to use a different CSS formatting style, consider using a tool like [Procssor](http://procssor.com/).
 
+If you would like to minify the file, you can use a tool like this [online CSS compressor using YUI Compressor](http://www.refresh-sf.com/yui/) or perform the minification as part of your build process.
+
 Browser support
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