Modified 'defaults' parameter object to explicitly reference 'jQuery' in...

Modified 'defaults' parameter object to explicitly reference 'jQuery' instead of '$' to prevent errors with jQuery.noConflict(), where '$' may not be defined on the window object. For instance, in my projects I use an AMD wrapper around jQuery.noConflict() which never exports '$' to global scope, so this plugin didn't work inside my requireJS modules until I changed the references to 'jQuery'. Hope that makes sense! :)