Solving "$ is not a function" on Wordpress

Add more compatibility. ( In my case, on WordPress, I have had the error “$ is not a function” )


More info:
* http://codeimpossible.com/2010/01/13/solving-document-ready-is-not-a-function-and-other-problems/
* http://elementdesignllc.com/2009/08/wordpress-jquery-is-not-a-function/